Performance Nutrition: Eating for Exercise Excellence

A great diet leads to great performance! If you want to gain muscle, not only do you have to pay your dues in the gym. You have to eat to gain as well. Our article Eating for Muscle Growth: When, How, and How Much to Eat for Adding Lean Mass covers your bases in that department.

However, muscle growth is not the only goal in sight when an athlete picks up the fork. For many, performance is the name of the game. Your goal might be to run faster, lift heavier weights, or jump higher. Of course, you want to perform your best, whether it’s on the running track or in the gym.

Your diet plays an important role here, too. You can’t eat too little and still expect peak physical performance. Carbohydrates and fat are sources of energy, and vitamins and minerals perform hundreds if not thousands of roles in your body, many tied directly to your body’s ability to function. So if not immediately when you eat, inadequate or imbalanced intakes could negatively affect your physical abilities and health in the long run.

The article you are reading right now explains everything you need to know about the importance of an excellent diet to perform your best. Regardless if you’re a lifter, a runner, or engage in any other type of physically demanding exercise, you’ll find helpful information here.

Everything from how crucial simply eating enough is to micronutrient requirements to a few scientifically proven dietary supplements that benefit your performance – keep reading, and we’ll take a closer look at the how, the when, and the what of eating for performance.

The Importance of Eating Enough for Health and Performance

It’s pretty self-explanatory: if you don’t eat enough energy, enough calories, you won’t perform your best.

Of course, you have thousands of kcals stored in your body, in your body fat, and in your muscle that you break down and use as energy if you don’t get enough from the foods you eat. That’s why you can keep performing pretty well even during a calorie deficit for quite some time, especially if you are an endurance athlete, since your body gets lighter and lighter and, therefore, faster.

Sooner or later, though, that energy shortage takes a toll in the form of declining performance. You’ll find it harder and harder to perform as usual, with a higher perceived level of effort to get through a workout.

When you eat fewer calories than you need to cover your energy expenditure, you lose a significant amount of the training effect. You break down both body fat and muscle tissue to cover the lack of energy from your diet. That means less efficient fuel for your muscles. It also makes it harder to get enough essential nutrients like protein, fat, carbohydrates, vitamins, and minerals. You need them all for optimal performance and health. Even if you somehow manage to maintain your exercise performance by using more of your own body as fuel, long-term deficiencies and a negative impact on your health will eventually catch up to you.

Low Energy Availability

If you train hard, you need to eat enough. Unfortunately, so-called low energy availability is a common problem among athletes, perhaps predominantly female athletes. Many things cause low energy availability. You might simply overestimate the amount of food and calories you need and eat. Your appetite might not sync with the caloric demands of your training. Your desire to have visible abs and low body fat year-round could lead to you not eating enough. Some people with naturally low body fat and a high energy turnover can walk around ripped all year, but not everyone can, not without negative consequences for health and performance. Also, eating disorders are not uncommon in sports.

A low energy availability increases the risk of adverse health effects, injuries, and a reduced ability to perform during exercise.

What is Low Energy Availability?

Energy availability is defined as “the difference in energy intake and exercise energy expenditure in relation to fat-free mass.”1

You might think of calories in minus calories out as the only critical equation for energy and energy expenditure. That’s what determines if you gain weight, lose weight, or if your weight is stable, after all.

When we’re talking about health and exercise performance, that equation is not the be-all and end-all. Energy availability is the number of calories you have left to cover your body’s essential functions once you subtract the calories you’ve spent during exercise. That’s a factor of crucial importance. If you don’t have enough energy left for your essential bodily functions, your energy availability is low. As a result, you have a relative energy deficiency.

How much do you need to eat to avoid low energy availability? Unfortunately, that’s not completely clear. For one thing, there are, as usual, individual differences and requirements from person to person. For another, men and women are different, with men getting away with a lower energy availability without the same negative consequences.

To make sure you have enough energy left, you need at least 45 kcal per kilogram of fat-free mass per day if you are female.2 That’s considered the limit where you have optimal energy availability for your physiological functions and exercise performance. There is not as much data on energy availability and the male athlete, but 40 kcal per kilogram of fat-free mass per day floats around as a fair estimate.3

Fat-free mass is everything in your body except, you guessed it, fat. If you weigh 70 kilograms with a body fat of 20 %, for example, your fat-free mass weighs 56 kilograms. Since 45 x 56 = 2,560, that’s the minimum number of calories you need to eat daily for optimal energy availability. Keep in mind that’s after you subtract the number of calories you spend exercising. If your workout burns 1,000 calories, that means your total calorie intake of the day should be 3,560 kcal.

Below are some examples of energy availability numbers for both men and women, from high to low.4

  • >45 kcal/kg of fat-free mass (females)
  • >40 kcal/kg of fat-free mass (males)

High energy availability and more than enough to cover the costs of your essential physical functions. Suitable when you want to gain weight and perform well. At least in the short run. An energy surplus means an increase in body weight. So if you mainly lift weights, you’ll probably keep getting stronger the heavier you get. If you’re an endurance athlete, though, a heavier body is a slower body.

  • 45 kcal/kg of fat-free mass (females)
  • 40 kcal/kg of fat-free mass (males)

Optimal and recommended energy availability for stable body weight and enough energy for health, performance, and physiological functions.

  • 30–45 kcal/kg of fat-free mass (females)
  • 30–45 kcal/kg of fat-free mass (males)

It could be ok during a limited time, such as an intentional weight loss using an individualized and healthy diet plan.

  • <30 kcal/kg of fat-free mass (females and males)

Adverse health effects and too few calories to properly maintain bodily functions, leading to reduced exercise performance and training adaptations.

Again, keep in mind that these examples are before you subtract the calories you spend during exercise. To get the total number of calories you need to eat, add however much your training session(s) required.

Salads are great, but if you have a high calorie requirement, they might not do the job.

Negative Consequences of a Low Energy Availability

As little as five days of a relative energy deficiency, with an energy availability of 30 kcal per kilogram of fat-free mass per day, leads to significant hormonal and metabolic disturbances.5 Decreased bone turnover and disturbances in luteinizing hormone pulses are just a couple of examples of adverse effects taking place in less than a week in women. In men, reductions in the hormones leptin and insulin take place in just as short a time.6

Short-term, low energy availability means a negative energy balance. In other words, you eat fewer calories than you burn, which leads to weight loss.

In the long run, your body activates defense mechanisms that decrease your basal metabolic rate through metabolic and physiological adaptations to prevent further weight loss and guarantee survival. Your body doesn’t know you simply want to look good naked. That mechanism is one of the misconceptions behind the term “starvation mode” from eating too little. Many people believe that means you’re an exception to calories in minus calories out. They think they are in a calorie deficit but still don’t lose weight. However, your calorie balance changes over time if you don’t eat enough. The energy requirements of your body decrease, meaning the number of calories that would have been a calorie deficit and weight loss no longer is a calorie deficit.

Starvation mode misinterpretations or not, the negative consequences of low energy availability are real. Noticing that your energy availability is too low can be tricky. Your body weight can be stable, and your body fat levels normal, even though your energy availability is low, leading to adverse health effects and decreased performance over time.7 8

If you don’t eat enough, your exercise performance drops due to the energy shortage. That’s not the only risk, though. A low energy availability also comes with an increased risk of several documented detrimental health effects. And maintaining good health should be reason enough to eat enough.

Hormonal Effects

Most studies looking at how low energy availability affects the hormones of athletes have female participants. Only recently has the research expanded to cover the male hormonal system as well. As a result, less is known about the effects of low energy availability in male athletes.

In women, the adverse effects are plentiful: disturbances in the stress axis or the HPA axis (the hormonal system controlled by the hypothalamus in the brain, the pituitary gland, and the adrenal glands), and changes in thyroid gland function. Alterations in the release of appetite and hunger hormones like leptin, oxytocin, ghrelin, peptide YY, and adiponectin are typical. Increased cortisol levels, growth hormone resistance, and lower levels of insulin and IGF-1 can also occur. These hormonal factors control how you break down and store fat and protein. So, likely, the negative response to a low energy availability is your body trying to protect itself by saving what energy is available for essential functions.

As we said, research in men and male athletes is still lacking. Short-term, low energy availability seems to affect hormones like insulin and leptin, but not testosterone or ghrelin. A long-term decline in testosterone levels is not out of the question, though. Trained men in endurance sports usually have lower testosterone levels than untrained men, and the association between endurance athletes and low energy availability is also well-known.9

Amenorrhea or Absence of Menstruation

Absent or irregular menstruation in female athletes is common. Many believe it to be a natural consequence of hard training per se, but that’s not the case. If you eat enough, it doesn’t happen, at least not nearly to the same extent. Absent menstruation in female athletes is often the result of hormonal effects caused by a relative energy deficiency.

Low energy availability and amenorrhea can lead to a loss of bone mass and even an increased risk of osteoporosis, a bone disease caused by a loss of bone mass large enough to make your bones weak and brittle. In addition, studies show lower bone density and bone strength in female athletes with absent or irregular menstruation.

The adverse skeletal effects also apply to males, usually documented in athletes whose low body weight is vital for performance, like jockeys, runners, and ski jumpers.

Resting Metabolic Rate

The calorie expenditure of an athlete is often very high, usually because of a lot of intensive training. Despite that, the athlete’s resting metabolic rate can be lower than average. If you increase your training volume without increasing your food intake simultaneously, the number of calories you expend during rest drops significantly in less than a month.10

That makes it harder to lose body fat. If you cut your calorie intake even further to lose weight when your energy availability is already low, you lose less weight than expected and find it harder to get rid of your body fat.11

Other Negative Health Effects

Amenorrheic female athletes with low energy availability have more unfavorable blood lipid profiles. Also, their blood vessels do not function quite as well as they should. Once these athletes start eating more and regain their menses, their vascular function improves as well.12

A compromised immune system is another consequence of low energy availability. Female runners without regular menstruation reported more frequent upper respiratory infections, perhaps because of reduced mucous membrane immune function, leaving them more susceptible to infections.13

Relative energy deficiency is a significant factor associated with illnesses, poor mental health status, sleep issues, and difficulty recovering from strenuous workouts in high-level athletes.14

Last but not least, and highly relevant to the topic of the article, a low energy availability does not allow you to perform as well as your should. If you train for performance, you need to give your body what it needs to be able to perform. And more than anything, it needs energy.

Diets, Body Composition, and Your Performance

Your body composition affects your physical performance as well as your health and how you look in the mirror. For example, most sports activities benefit from plenty of muscle mass and not too much body fat. “Plenty of muscle mass” might be a diffuse concept. Perhaps “enough” would be better. In some sports, more muscle always equals better performance, but not in all. A long-distance runner, for example, needs enough muscle mass to move his or her body forwards as efficiently as possible, but any more than that means unnecessary ballast.

One of the main goals of a performance-enhancing diet is to provide you with the energy and nutrients you need to attain the optimal body composition for your sport.

Plenty of popular diets aiming to improve body composition deviate more or less drastically from regular dietary recommendations. From low-fat diets with large amounts of carbohydrates to ketogenic diets almost devoid of carbs. These all seem to be of equal effectiveness.15 Your personal preferences should probably decide which, if any, is suitable for you.

One thing uniting all diets suitable for high-performing athletes is a relatively high protein intake. That is because you need more protein than the average person to build muscle and to repair broken-down muscle fibers following your workouts.

You can vary the amount of fat and carbs in your diet pretty much however you like. Even though carbohydrates are considered the best fuel during exercise, your body is adaptable enough to perform pretty much the same long-term if you replace them with fat.16 17 18

Most studies deal with endurance training. However, according to the available research, your performance in the gym doesn’t seem to be negatively affected by a low-carbohydrate diet, either.19 A recent study on bodybuilders demonstrated that a ketogenic diet could hamper your muscle-building efforts, though.20 Therefore, a diet completely devoid of carbs might not be the best idea, at least not if you want to build as much muscle as possible.

There are reasons why current recommendations suggest that athletes should eat plenty of carbohydrates. First, you can use carbs as energy over a wide range of exercise intensities and regardless of how hard you train. Your body has a more challenging time utilizing fat as fuel if you increase your intensity. Also, your carbohydrate stores are limited to a few hundred grams, unlike fat, of which you have a practically unlimited supply. And, you’ll be hard-pressed to find an Olympic athlete in a sport requiring physical performance who excludes carbs and gets better results from doing so.

Protein, fats, and carbohydrates are the so-called macronutrients in your diet. But, of course, alcohol is also a macronutrient. It won’t add much to your exercise performance or help your gain muscle, though.


The three energy-yielding macronutrients, protein, carbohydrates, and fats, all contribute to your physical performance. However, depending on the volume and intensity of your training, you can utilize them differently.


To build muscle, you need protein. Aim to get somewhere between 1.6 to 2 grams of protein per kilogram of body weight per day. That’ll make you sure your muscles have all the building material they need.21 22

If your diet is purely plant-based, 2 grams of protein per kilogram of body weight per day should be the minimum. Vegetable proteins are not quite as good as animal proteins for building muscle on a gram-for-gram basis. You get less of the amino acids you need to build muscle from plant-based protein sources. Therefore, you need to compensate by eating more of it instead.

Those amounts are suitable for performance, even if you don’t care too much about building muscle. Endurance training increases the amount of protein you need as well. Regardless of what type of exercise you engage in, getting plenty of protein lets you perform better. All your bodily tissues require protein for repair and growth.

During periods when you increase your training load or amount, or if you’re in a calorie deficit trying to lose weight, you can make use of even more protein.

While your total daily protein intake is the most important factor, your should try to spread it out in the form of more frequent meals of 0.3–0.4 grams of protein per kilogram of body weight per meal separated by 3–5 hours, plus following a workout. You always take up all the protein you eat, regardless of meal frequency, but you can’t use more than that to build muscle.23 24 25

If you don’t get enough protein from your regular diet, a protein supplement is cost-effective and convenient. Most probably think of protein supplements as something intended for building muscle, but studies with endurance athletes show that protein supplements help with recovery and performance.26 27


Just like protein, fat is an essential nutrient. You use the fat in your diet as a source of energy to repair and keep your cells healthy, maintain optimal brain and nervous system function, and make hormones. Also, fat adds taste to your food and keeps you feeling full longer.

Fat provides you with more than 9 kcal per gram, more than twice as much energy as you get from protein or carbs. The fat you eat isn’t a crucial source of fuel for a workout a few hours later. You use fat to fuel your workouts, as long as the intensity isn’t too high, but you already have enough of it stored in your body fat to keep you going for several marathons.

Try to get at least 20% of your daily calories from fat.28 During specific periods, like losing weight with a low-fat diet, it’s OK to go lower. However, fat is essential for your hormones, health, and physical performance. If you eat too little, you might compromise your training results and your well-being.

When you rest or perform light, low-intensity activities, your muscles rely on fat as an energy source to a large extent. However, if you ramp up the intensity, like during a weight training session or when you run at or near your maximal capacity, fat doesn’t cut it anymore. Instead, your body turns to carbohydrates to keep the intensity up. Now, if you remove the carbs from your diet, your body adapts. It learns how to use fat to fuel even fairly high-intensity work. There are no known advantages to eliminating carbohydrates and replacing them with fat if your goal is peak exercise performance, though.

Regular endurance training also improves your capacity to use fatty acids as fuel when you perform high-intensity work.29

Most official recommendations tell us we should limit saturated fat to about a third of our total fat intake, or 10% of our total calorie intake. Saturated fatty acids are considered a significant risk factor for heart disease. Some authorities recommend limiting saturated fat to no more than 5% of your energy intake. One example is the American Heart Association. It’s a hot topic, though, and not all scientists and experts agree. Some think that saturated fat does not deserve the bad rep it has.30

Most experts agree that polyunsaturated fat, with omega-3 fatty acids leading the pack, is healthy. The three most crucial omega-3s are ALA, EPA, and DHA. You find the last two primarily in fatty fish, which get them from the algae they eat.

If you don’t eat fatty fish often, a high-quality omega-3 supplement can help you get enough. Athletes looking to perform and to get anti-inflammatory effects along with the associated health benefits should aim for 1–2 grams of EPA plus DHA with a ratio of 2:1 EPA to DHA.31


How do you spell the best fuel for high-intensity workouts? 


How much and how hard you train determines your carbohydrate requirements. “Requirement” might be the wrong word since you don’t need a single gram of carbohydrate to live a healthy life. However, if you’re looking for exercise performance, speaking in terms of requirements is not wrong.

  • Low-intensity or skill-based exercise doesn’t require a lot of carbs. However, according to scientific recommendations, you should aim for 3–5 grams of carbohydrates per kilogram of body weight per day. Most likely, you can get away will less if you prefer a low-carb diet without losing any performance benefits.
  • If you perform moderate-intensity exercise about an hour a day, your recommended carbohydrate intake is 5–7 grams per kilogram of body weight per day.
  • Endurance exercise for 1–3 hours per day requires 6–10 grams of carbohydrates per kilogram of body weight per day for optimal performance and recovery.
  • If you’re a hardcore endurance athlete, training more than 4–5 hours a day, your carbohydrate requirements increase to match your training volume: 8–12 grams per kilogram of body weight per day.

These are amounts recommended in scientific literature, based on many decades of research.32

If you’re mainly interested in lifting, you have it easier. There is no evidence that you need a certain amount of carbohydrates to perform well or build muscle and get stronger. So you can go with what you prefer. 

According to current recommendations, strength athletes need 3–7 grams of carbs per kilogram of body weight per day. There is nothing wrong with those amounts, but the recommendations are based on old and perhaps outdated theories. Recent research can’t find any advantages to any particular daily carb intake unless you feel you prefer a certain amount that makes you perform your best.33 As we mentioned earlier, one study found that a ketogenic diet utterly void of carbs hampers muscle growth in bodybuilders a bit.

Perhaps the most extreme variants simply aren’t optimal, especially for strength athletes? For example, if you don’t eat any carbs at all, you might not build as much muscle, and if you eat the amounts recommended for an endurance athlete, you’ll probably gain more fat than muscle.

If you have determined your daily calorie intake, you should decide how much protein and fat you’re eating. Those are the two essential macronutrients you need to live and stay healthy. The remaining calories are carbohydrate calories.

An example:

  • Your target is 3,000 kcal.
  • You weigh 80 kilograms and aim for 2 grams of protein per kilogram of bodyweight. Protein provides you with 4 kcal per gram, which gives us the equation 160 x 4 = 640 kcal from protein.
  • Also, you want 25% of that 3,000 kcal to come from fat. That means 3,000 x 0.25 = 750 kcal.
  • One gram of fat provides 9 kcal, which means 750 / 9 = 83 grams of fat.

There you have it. That’s all there is to calculating your carb intake.

  • 750 + 640 = 1,390 kcal meaning you can subtract those calories from your total calorie intake. 3,000 – 1,390 = 1,610 kcal from carbohydrates.
  • Just like protein, carbs give you around 4 kcal per gram. That gives us 1,610 / 4 = 402.5 grams of carbs. Or 400 grams rounded off and ready.

There is no evidence that you gain more or less muscle depending on which carbohydrate sources you eat. As for exercise performance, research suggests that a meal that increases your blood sugar moderately over a long time is preferable to a meal that increases your blood sugar rapidly.34 However, the evidence is weak.

These are some great carbohydrate sources, nutritious and filled with energy, and suitable for anyone looking to perform well:

  • Bread
  • Pasta
  • Grains
  • Rice
  • Potatoes, both regular and sweet potatoes
  • Bulgur
  • Quinoa
  • Beans
  • Lentils
  • Fruits
  • Berries
  • Vegetables

It’s probably not a good idea to base your carbs on refined foods alone. However, if you need a lot of energy to fuel your workouts, it might be tough to get enough from unrefined grains, legumes, fruits, and vegetables. Not only does it mean a ton of food to eat, but you might also find your stomach rebel against you because of all the fiber.

Your carbohydrate staples should be nutritious, but don’t be afraid to resort to refined carbohydrate sources or even ones based on sugars. When you need a lot of energy to fuel your high-intensity workouts, you need the fuel.

Timing Your Meals for Performance

Most people perform better after eating than on an empty stomach. There are exceptions, those who experience the opposite, but in general, most of us handle high-intensity workouts better with a carbohydrate meal in the system. At least if you’re doing endurance-type activities and they last longer than an hour.35 36

Current recommendations for athletes are 1–2 grams of carbohydrates per kilogram of bodyweight 3–4 hours before a workout for optimal performance.37 Or course, as with most things, there are individual responses to carb intake. Some find that they perform their best fasting and feel sluggish from pre-workout carbs. If that sounds like you, you’re probably better off listening to your body than force-feeding yourself carbohydrates. However, if your training sessions are long, it’s unlikely that you can keep the same intensity up in a fasted state as you could in the fed.

Eating many carbs pre-workout seems to be beneficial, at least if your stomach can handle it. A meal providing 1.1 grams of carbohydrates per kilogram of body weight an hour before training is good, but 2.2 grams per kilogram is even better.38

According to the available research, shorter workouts don’t require any carbohydrates or even any food. You have enough energy stored in your body to get through an hour of exercise, even if you have fasted for a long time. However, during really high-intensity work, eating or drinking some form of carbs half an hour before training can improve your performance a bit, even when the workout is short.39

As for strength training, there is no clear-cut scientific answer. Most of the available studies do not find any particular benefits or drawbacks to eating or not eating before working out.40 41 Try for yourself. If it feels good training on a full stomach, there are no negative aspects to doing so. What studies say isn’t always of practical relevance if you find yourself performing better by doing something else. Hit the gym on an empty stomach or after a meal according to your preferences. As long as you eat or drink some form of protein post-workout, your gains won’t suffer.

When it’s time to do some high-intensity interval training, it doesn’t seem to matter if you have eaten or not. Unless you feel differently, of course.42 43

Fluid Balance and Exercise Performance

Water is the most critical nutrient for your survival, second only to oxygen. Your ability to perform at a high level also depends on water. Plenty of studies show that your physical performance, strength, power, and endurance all suffer if you don’t drink enough.44 45 46

Drink too little, and you can forget performing your best.

If you lose 3–4% of your body weight from sweating, you lose 2–3% of your strength and a whopping 10% of your muscular endurance at the same time. If you work out in a hot environment and know beforehand that you’ll be pouring sweat, it’s a good idea to load up on fluids ahead of time. Drink half a liter 1–2 hours before your workout, and follow up with regular fluid intakes during the training itself, to replenish what you lose by sweating.47 Somewhere around 250 mL every 20 minutes is a sensible practice during exercise in the heat.48

If you end up drenched in sweat, you have also lost salts and minerals. Sports drink manufacturers take advantage of this fact and want you to pour their products down your throat to perform well. However, you only benefit from ingesting salt and electrolytes during your training sessions if you work out in high temperatures, sweat copiously, and your workout lasts for longer than an hour. If that’s the case, drinking 600–1,200 mL per hour and adding 0.5–0.7 grams of sodium per liter of fluid is a good idea.49

Many commercial sports drinks have you covered in that department, but you can save money by making your own, maybe adding some flavoring agent for taste. Sugared ones work fine, even better if you need the energy. Sure, your teeth might complain, but there is no performance disadvantage to consuming carbs during your workout. On the contrary, they can help you perform better.50 If you find it tough to drink enough during exercise, the sweet taste can drive thirst and help you with rehydration. Of course, you can always drink pure water without any added flavor, but keep in mind that saltwater might not be very palatable. 

During workouts lasting no longer than an hour, water is enough.

Performance-Enhancing Supplements

A good diet covers most of your nutritional needs, both for health and physical performance. However, a select few dietary supplements offer proven performance boosts you can’t get from your regular diet. That is because either the active substances are absent in most foods, or you get them in too small amounts to benefit from them.

The supplement store shelves, be they physical or virtual, are loaded with pills and powders claiming to enhance your performance. Some are scams, some lack scientific evidence. Others come backed by that evidence but with a minor effect in a real-life scenario outside the lab.

Some stand out from the rest. Dozens or even hundreds of controlled trials support these supplements and verify their performance-enhancing effects. Effects that you notice, not just measure in a laboratory mouse.

The three that stand out are creatine, caffeine, and beta-alanine.


Most of you probably know the benefits of creatine for improving performance by now. Creatine is a dietary supplement that makes you stronger, faster, and more explosive, and that has rock-solid scientific evidence backing it. It’s also a supplement without adverse side effects.

You can read much more about creatine, what it is, and how to use it in our comprehensive guide, Creatine: Effects, Benefits, and Safety.

In summary:

  • A week-long loading phase will kick-start the effects by filling your muscles with creatine. Take 20 grams a day divided into four intakes during the day.

You can skip this loading phase if you want and go directly to the next step. The result is the same. It’ll just take a little longer without the loading phase.

  • Switch over to 3–5 grams of creatine per day once the loading week is over.

If you already carry a lot of muscle, you might get an even better effect with 10 grams per day. You can keep using creatine continuously if you want, although one old study suggests a diminished effect after some weeks. A 4–6 week break from creatine usage every third month would mitigate this diminished effect, but then again, it’s unclear if it even exists or if cycling creatine or using it non-stop is best in the long run. Regardless, it’s not harmful to just keep using creatine year-round.

  • The best opportunity to take creatine is after a workout, along with something that stimulates insulin release, meaning carbs or protein. That’s when creatine is sluiced into your muscles and stored there the most efficiently.

One study demonstrated that post-workout creatine supplementation led to “superior gains” compared to pre-workout supplementation.51 And who doesn’t want superior gains? If you prefer to take your creatine at some other time, it’s not bad, only possibly a little less good. Creatine has no acute effects right after you’ve swallowed it. It’s all about building up large stores of creatine in your muscles. According to a few studies, the best time to accomplish that is to take creatine after working out.

  • Take creatine on your days off from training as well, along with a meal of your choice.
  • Creatine monohydrate is the best and most cost-effective form of creatine. Many other types of creatine are available on the market, but no other has yet proven more effective than the original.


Like creatine, there are few doubts that you perform better with a bit of caffeine in your system. Or perhaps quite a lot of caffeine. Unlike creatine, though, we’re not talking about building up caffeine stores in your muscles, but about an acute effect the hours after getting caffeinated.

Some research shows that you build up one thing when you regularly use caffeine: tolerance to the substance. That means that you might not the effects you want from caffeine if you use it before every workout. To ensure you get the maximum benefit from your caffeine, consider saving it for training sessions where you feel sluggish and need a boost.

Taking 3–6 milligrams of caffeine per kilogram of body weight an hour before lifting, running, or whatever your exercise of choice is, lets you perform better and longer before fatiguing. Those are safe doses, proven effective in countless studies, although some people don’t seem to get the same performance boost as others from caffeine.

Your source of caffeine doesn’t matter. Pure caffeine in pill form, energy drinks, caffeinated chewing gum, or good old coffee – they all work. The problem with getting your caffeine from regular coffee is that you have to drink several cups to get enough for the performance-enhancing effect. Not everyone wants half a liter or more of coffee sloshing around in the stomach when it’s time to hit the squat rack or the track. Also, it’s easier to dose your caffeine accurately with pills since a cup of coffee can contain different amounts of caffeine depending on how you brew it and which blend you use.

Feel free to peruse our thorough article about everything coffee and caffeine if you want more in-depth info!


Beta-alanine is popular both as a stand-alone supplement and as part of so-called pre-workout products or PWOs. Plenty of scientific research support beta-alanine as a performance-boosting supplement. You can read more and find out everything you need to know about beta-alanine in our dedicated article.

Even though it is an amino acid, beta-alanine does not build muscle by itself. Instead, beta-alanine increases the levels of carnosine in your muscles. High carnosine levels delay muscular fatigue and allow you to perform better.

Beta-alanine works the same way as creatine in that regard. That means, also like creatine, that you don’t get any performance boost right after ingesting it. There is no real physiological reason for having beta-alanine in a PWO besides the fact that it also makes your skin tingle. Some people feel extra motivated to train once that effect kicks in. It doesn’t improve your performance, though. The results of beta-alanine come from building up high levels of carnosine in your muscles, thereby allowing you to perform a little better. In other words, don’t expect any benefits from beta-alanine if you only use it now and then to get the tingling sensation.

Beta-alanine improves performance in exercise tasks lasting four minutes or less.52 It’s not a supplement for long-distance runners. If, on the other hand, you’re lifting weights or engaging in some other type of high-intensity exercise, beta-alanine could be worth trying.

An effective dose is 3.2–6.4 grams of beta-alanine per day for about a month. Then you’ll have loaded your muscles with carnosine and can lower your daily dosage to the maintenance dose of 1.2 grams per day for however long you want.

You don’t need any of these supplements to see good results from your training. However, if you want to perform a little better than usual, they might be worth exploring. If you’re mainly into strength training and pick one supplement, creatine is probably the best option.

Protein “supplements” are simply food in powdered form, which is why we don’t include them here. If you count protein powder as a supplement, though, it’s number one if you need more protein.

Something you really need, both for your health and perform well, and indeed to live, are micronutrients.

Micronutrients and Performance

In this part of the article, you’ll find the info you need about vitamins and minerals that benefit your training. But, perhaps surprisingly, a few can even impede your training progress if you take them in large amounts.

You can cover most of your vitamin and mineral needs with a balanced diet, and in most cases, you don’t perform better or build more muscle by taking a supplement. However, you might not perform as well as you should if you get too little of them, which is why all athletes benefit from keeping track of their micronutrient needs and intake.

Of course, all vitamins and minerals are essential, but the following stand out: they play crucial roles in the ability of your muscles to handle high-intensity work and peak performance.

Vitamins are important, but try to get them mostly from your regular diet.


Calcium is the most abundant mineral in your body, and 99% of it can be found in your bones and teeth. When it comes to the ability of your muscles to perform physical work, however, the last percentage is the important one.

That’s because your muscles need calcium to be able to function and perform properly. In addition, without access to enough calcium, your blood vessels and nerves can’t satisfactorily perform their physiological duties.

Every time your muscles contract, calcium is pumped into your muscle fibers. Without that pumping effect, your muscles can’t contract properly. When you relax your muscles again, calcium is pumped out of the fibers.

High-intensity exercise partially depletes the calcium in your body.53 Relax – that doesn’t mean that you’ll automatically suffer calcium deficiency if you exercise a lot. However, it does mean that you should make sure you get enough calcium daily. Quite a large number of Americans don’t get enough calcium from their diet.54

Calcium supplements don’t improve exercise performance in athletes who aren’t deficient.55 In other words, don’t spend money on calcium supplements unless you have a diagnosed deficiency. Instead, what you should do is eat and drink enough calcium-rich foods to cover your needs.

The recommended daily intake of calcium is 1,000 milligrams in the US. So if you work out hard regularly and lose calcium through your training, it’s a good idea to make sure you don’t fall below that intake.

Avoid high-dose calcium supplements if you don’t have a medically documented need of them. Not only do they not improve your performance, but large amounts of calcium, especially with high doses of vitamin D, can lead to too much calcium in your blood, so-called hypercalcemia. The acute effects of hypercalcemia include constipation, feeling excessively tired, and muscular weakness. Over time, you could develop kidney stones and other kidney problems. In men, large amounts of calcium are also associated with an increased risk of prostate cancer.

If you don’t use dairy products or follow a calorie-restricted diet to lose weight, getting 1,000 milligrams of calcium per day can be tricky.

If you’re vegan or can’t or won’t use dairy for some other reason, you don’t have access to very many concentrated dietary calcium sources. Leafy greens give you a lot of calcium, but they also contain oxalates which prevent you from absorbing the calcium properly. If you know you can’t get enough calcium through your food, a supplement can help you get there. Avoid over-dosing, though, for the reasons mentioned above. Also, plant-based “milk products” are often fortified with calcium, so getting enough calcium even with a completely vegan diet should be quite possible.

Vitamin D

Low levels of vitamin D could lead to reduced exercise capacity and sub-optimal training results. 56 No evidence shows that either athletes or casual fitness enthusiasts need more vitamin D than the average person, but many get too little.

Our primary sources of vitamin D are the sun and fatty fish. Most other foods are poor sources of vitamin D, and if you live in the northern hemisphere, getting enough sun can be a challenge. Even if you are out and about in the sun, it’s not strong enough to give you meaningful amounts of vitamin D during the winter months.

That means that vitamin D is one of the few vitamins where supplementation is prudent for most, perhaps especially if you exercise regularly and want peak performance. A meta-analysis from 2017 showed that vitamin D supplementation of up to 5,000 International Units (IU) could increase your strength by 19%.57 

If you, like many others, don’t get enough vitamin D from your diet and the sun, a supplement is beneficial. A daily dose of 2-4000 IU (corresponding to 50-100 micrograms) makes sure you get enough both for health and performance, without any documented side effects.

Want to learn more about vitamin D? You’re in the right place. We have an article on the topic, just for you.


You use iron to produce blood and to deliver oxygen to your muscles. Fertile women are at an increased risk of unsatisfactory iron status than men. Female athletes are at an even greater risk. 58 The combination of too little dietary iron, menstruation, iron losses through sweating, and possibly acute inflammation caused by training makes it hard for female athletes to get enough.

Poor iron status is associated with lower exercise performance.59 If you’re female, fertile, and exercise regularly, it’s extra vital that you get enough iron. Try to do so through your regular diet by adjusting it if necessary. Getting too much iron from supplements is not a good thing and brings adverse effects of its own. Pregnant women can often benefit from iron supplements, though, but seek proper medical advice first, so you don’t get too much of a good thing if you don’t need it.

The best sources of iron are offals, like liver and blood-based foods. Meat and eggs also provide plenty of iron. The type of iron you utilize most efficiently is heme iron. You can only get heme iron from animal-based foods. If you only eat plant-based foods, your get so-called non-heme iron from nuts, legumes, and whole grains. The problem is that the uptake for non-heme iron is not very good compared to heme iron. And the uptake of heme iron is poor, to begin with, somewhere between 15 and 35%.

You can improve your uptake of non-heme iron by eating iron-rich foods with vitamin C-rich fruits and vegetables. However, other substances, like tannins in coffee and tea, and calcium in dairy products, inhibit the uptake of iron even further. So try to avoid those, at least in the same meal as your iron-rich food sources.

Fertile women need 18 milligrams of iron per day, an amount that can increase up to 27 milligrams per day during pregnancy.60 Men and postmenopausal women need 8 milligrams per day.

Vitamin C and E

Too much of a good thing is too much. That’s the takeaway of studies where athletes take large doses of vitamin C and E.

Both these vitamins are essential antioxidants you need to get from your diet. They protect your cells from damage, including damage from the stress of your training sessions. However, that doesn’t mean that you should use high-dose supplements of vitamin C and E. On the contrary, doing so could diminish the positive effects and adaptations of endurance training and strength training.61 62

Even when analyses don’t observe any such adverse effects, they conclude that you don’t gain any advantages or positive effects either.63 At best, it’s a waste; at worst, it could prevent your training results.

That only happens if you supplement vitamin C and E, not if you get them from regular foods. Try to get the amounts you need from a varied and balanced diet, and only use a moderately dosed supplement if you can’t get enough from foods. How much is enough? EFSA, the European Food Safety Authority, concludes that 110 milligrams of vitamin C per day cover the requirements of 98% of the population.64 As for vitamin E, they recommend a daily intake of 13 milligrams for men and 11 milligrams for women.65

If you want to make sure you get enough to cover any potential additional needs your exercise might create, use a 200-milligram vitamin C supplement. That amount is enough for everyone and has no adverse side effects. There is no evidence that supplementing with vitamin E is beneficial for athletes. On the contrary, doing so might be counterproductive.66 67

Want to learn more about dietary supplements? Which ones are worth your money, and which are questionable or useless? Check our StrengthLog’s Supplement Guide, our free guide where I review 26 of the most popular supplements.


  • If you don’t eat enough, don’t expect to perform your best. A low energy availability leads to a lower metabolic rate and hormonal disturbances. It also leads to menstrual dysfunction and can weaken your bones if you’re female.
  • Protein, fat, and carbohydrates are all important to exercise performance. The optimal amounts for building muscle are also suitable for peak performance.
  • Aim for two grams of protein per kilogram of body weight per day.
  • At least 20% of your energy intake should come from fats.
  • How active you are and how much you exercise determines your optimal carbohydrate intake.
  • Eating a carbohydrate-rich meal 3–4 hours before a training session improves performance.
  • Creatine, caffeine, and beta-alanine can boost your performance. Caffeine does it right after ingestion, while the other two do so with long-term use.
  • Vitamin D, iron, and calcium are important for your muscle to function and perform properly. Get your micronutrients from regular foods if you can. Vitamin D is the exception where a supplement is often advisable.
  • High-dose supplements of vitamin C and E do not improve your exercise performance. In fact, they can impair your training results.


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Andreas Abelsson

Andreas is a certified nutrition coach with over three decades of training experience. He has followed and reported on the research fields of exercise, nutrition, and health for almost as long and is a specialist in metabolic health and nutrition coaching for athletes. Read more about Andreas and StrengthLog by clicking here.