Protein powder really increases body mass

Sport: Interview: What do protein shakes really do

Many athletes who lift weights in gyms want one thing above all: build muscles quickly, get their bodies in shape. To do this, they often use special protein drinks or energy bars. The physician Christine Graf explains what such products really do and how athletes can eat in the best possible way

GEO KOMPAKT: Professor Graf, almost all fitness studios offer protein shakes for building muscle. What use do they have?

PROFESSOR CHRISTINE GRAF: For the average recreational athlete: none. Many people consume these drinks, but they only offer real added value - if at all - to athletes who train very, very hard. Of course, everyone needs protein to build up and maintain their muscles, but normal fitness enthusiasts take in enough food every day. Such drinks can even be counterproductive for those who want to lose weight.


Because the powders used in the drinks are often high in sugar. Therefore, I usually advise against it.

How much protein does an athlete need?

On average, 0.8 grams of protein per kilogram of body weight per day. However, Germans consume an average of 1.1 grams of protein per kilo of body weight a day. The recommendation is only higher for real endurance and strength athletes: 1.2 to a maximum of 1.7 grams per kilo of body weight. Additional proteins are therefore only useful for those people who train particularly intensively - i.e. who do competitive sports several times a week. None of the others need this addition.

Many amateur strength athletes want to develop clearly visible muscles as quickly as possible. Can protein powder speed this up?

Yes. High-quality protein drinks or protein bars after exercise can be a practical - albeit very expensive - help. But it is much more important that you train adequately and effectively. Because an extra serving of protein alone does not grow muscles. Unfortunately, many do not want to admit that and prefer to mix their powder three times a day, believing: A lot helps a lot. In fact, if you only go to the gym once a week at the same time, there is little point in building muscle.

How do I recognize a high quality protein drink or bar?

You should pay attention to a low fat content and take German products, foreign ones sometimes contain traces of anabolic steroids.

Can too much protein be harmful?

Naturally. Almost every nutrient overdose has side effects. Excess protein is used by the body's cells to generate energy: this creates waste materials that put a strain on the kidneys. However, it usually only becomes dangerous if kidney function is impaired. A protein-to-carbohydrate ratio of between one to two and one to four is recommended (you should therefore consume two to four grams of carbohydrates per gram of protein). In addition, it makes more sense to eat proteins from natural foods, this way you run less risk of overdosing yourself or eating too one-sidedly.

Would you rather eat a steak?

Meat is not necessarily the food of choice because, as an animal-based food, it is often high in fat and increases the cholesterol level. The same goes for eggs. Healthier sources of protein include fish, low-fat dairy products, and some plant-based products, such as legumes such as lentils and beans or nuts. Incidentally, you can make it easier for the body to absorb protein by consuming it with products rich in carbohydrates. For example, muesli with milk, potatoes with egg, lentil soup with bread or beans with rice. In addition, these combinations also increase the biological value of the proteins. This means the amount of body protein that can be built up from 100 grams of dietary protein.

Can athletes who live vegan get enough protein?

Vegans run the risk of inadequate care. You should therefore make sure that you consume enough protein in total. Vegetarians and vegans are often plagued by a completely different nutritional problem: iron deficiency. Incidentally, many women also because they lose a lot of iron through menstruation. The body needs iron, for example, to make red blood cells. They supply cells and muscles with oxygen. So if you feel exhausted during exercise unusually quickly, if you are constantly tired, iron deficiency could be behind this. The best way to get iron is through meat or fish. Or you can drizzle a few drops of orange juice into the muesli in the morning, because the fruit acid supports the absorption of iron from the grain in the intestine.

Do athletes generally have an increased need for certain nutrients?

Only athletes who train intensively - preparing for a tournament or a marathon, for example - need more vitamins or micronutrients, including iron, copper, zinc, selenium or magnesium. However, physically active people take in larger amounts of these micronutrients anyway, as they consume more energy and therefore eat more overall. In this way, the increased need is mostly balanced out by diet alone. It looks very different when people follow a strict diet and at the same time train for a marathon, for example. In this case, deficiency symptoms are quite likely.

Can you lose weight through exercise alone without restricting your diet?

Practically not. Studies have shown that a person needs to exercise or exercise for at least an hour a day to lose weight. Only professional athletes can do that. But I also consider this link to be wrong and misleading. Because food is food, sport is sport. And you shouldn't do sports to lose weight - but because it's fun and healthy. At a time when most of us sit in front of the screen all day, we need this balance more urgently than ever.

Nevertheless, it is interesting for many to know how many calories the body consumes, for example, when running.

The rule of thumb is that 100 kilocalories are consumed in ten minutes of jogging. A whole hour of jogging is equivalent to 600 kilocalories - that's a bar of chocolate. The following example is even more memorable: To burn a lump of sugar, you have to take 500 steps.

When do you actually burn sugar during exercise and when do you burn fat?

You always burn fat, even when you are resting - i.e. when you are not active at all. The rumor persists that fat burning only begins after about 30 minutes of physical activity. This is wrong. Our body cells can fall back on fat as well as on carbohydrates - i.e. sugar - at any time. The advantage of sugar is that it burns a little faster and, in an emergency, it can also be used without oxygen. To burn fat, however, the body always needs oxygen and - to stimulate it - carbohydrates.

What does that mean in practice?

For example, when you start panting on the treadmill, the body works at full speed to supply the muscles with sufficient fuel. However, the body's ability to absorb oxygen to burn fat and sugar is limited. Therefore, at a certain point, the muscles start converting sugar into lactic acid - without consuming additional oxygen. Which also generates energy.

Is this kind of muscle acidification harmful to your health?

No, many believe that, but it is not true. In any case, nobody can last long in an over-acidic state. Because lactic acid production is an extremely inefficient form of energy use that is only intended for short periods of exposure. In this way, the reserves of the sugar stored in the muscle are already used up during a half-minute sprint or an intense football game. After one to three minutes at the latest, you become exhausted, then nothing works anymore. Everyone has experienced this before. This effect occurs, for example, when you run after the tram and then gasp for breath.

What is the ideal level of exertion in order to burn as much fat as possible?

The lower the intensity, the more fats are used and the body saves carbohydrates. There is a simple test for this: if you are jogging and can still speak, the ratio is ideal. Or when dumbbells can be lifted about ten to twelve times in a row. With regular, moderate training, the percentage of fat consumption can even be increased, because then the necessary enzyme systems in the cells multiply. What many do not know either: Even the half-minute sprint just described can have an effect on fat use. But only afterwards.

How so?

If you do not eat something again immediately after a short, intense exercise, the carbohydrate stores of the muscles and liver are replenished from the body's own fats. So the body converts fat into sugar instead of burning it.

Can it happen that the body burns muscle protein while exercising?

Usually not. The only danger is if you are severely underweight or on an extremely hungry diet. Conversely, when dieting, you can even counteract muscle loss, which often occurs as an undesirable side effect, through exercise. And basically the average German nowadays has enough carbohydrate and fat reserves that can be used to provide energy during exercise. Competitive athletes, on the other hand, have to supply themselves with sufficient carbohydrates before a great effort, when intense and, above all, long loads are pending, for example before a marathon. This then happens, for example, at the "noodle parties".

What's it all about?

A few days before a competition or a marathon, the athlete first "empties" his body's own sugar stores: through a lot of training and the lowest possible consumption of carbohydrates. On the evening before the competition, the athlete then eats large amounts of carbohydrates, mostly in the form of pasta. The liver and muscles are then so starved that they suck up the carbohydrates like a sponge and literally overload their sugar stores. As a result, the athlete has significantly more energy available the next day.

Should you eat while exercising?

You only need additional energy if you have been doing sports for more than an hour. In a longer tournament, it makes sense to consume carbohydrates in between. For example, you can eat an energy bar. You should make sure that the ratio of carbohydrates to fats - which is stated on the packaging - is six to one, this is optimal. Energy gels or special isotonic sports drinks - i.e. drinks in which the concentration of dissolved substances is just as high as in human blood, so that they can be absorbed particularly quickly from the intestine into the body - are even more effective. In general, however, you do not have to buy such sports drinks, you can easily make them yourself.

Can you give us a recipe?

I recommend mixing 70 grams of glucose or honey with a liter of tea or still mineral water. If you don't like it so sweet, you can also take maltodextrin - this is a sugar that is well tolerated and tasteless. With this mixture you get an optimally composed sports drink. If it is very hot, you can also add a pinch of table salt to compensate for the loss of salt through sweating.

Do such drinks increase performance?

Yes. We tested these self-mixed drinks with children at a soccer tournament. They drank it in every break. In contrast to previous competitions, their performance was maintained throughout the game. That was very impressive and confirms the available studies.

What do you think of energy drinks?

Nothing. They contain a lot of caffeine, which increases blood pressure and heart rate and can stress the circulation during exercise.

When should you drink anything while exercising?

If you have been exercising for less than an hour, it is best to drink only water without any additives - half a glass before exercising. If you do sport for more than an hour, you should drink 200 milliliters of water or the sugar solution just mentioned every 15 minutes. However, you shouldn't consume too much, as this can lead to a stitch in the side or stomach ache. After exercising, you should use water to make up for the loss of fluids.

What happens if you drink too little?

You feel dizzy and uncomfortable, suffer from difficulty concentrating and headaches. Performance decreases from as little as two percent water deficiency. The best way to determine the loss of fluid is to use the scales - nobody should be more than 500 grams below their normal weight, otherwise it will be critical. If you don't have a scale, you can also use urine as a guide. If its color is very yellow, you should definitely drink something. A third possibility is the skin fold test: If the skin on the back of the hand "remains" for a while when you pull it up a little, you suffer from an acute lack of water.

You keep hearing that you lose minerals when you sweat. Can this be a problem?

The main thing that the body loses when you sweat is sodium. Therefore, you should never drink water that is low in minerals during exercise - and also not consume fluids continuously: If in doubt, this will flush out too much sodium. This can lead to dangerous cardiac arrhythmias and, in the worst case, even death in marathons. The sweat itself adapts to a certain extent. In the case of experienced extreme athletes in the desert, for example, who sweat a lot, the sweat is lower in sodium. Nevertheless, as a precaution, you should mix some table salt into your drink when it is very hot to compensate for the sodium loss. Frequent cramps can also be an indication of a mineral deficiency.

Apparently it makes a difference how intensely you train and what you want to achieve. So what should a recreational athlete pay attention to in his diet?

As long as he feels fit and does less than an hour of uninterrupted sport, a balanced mixed diet is completely sufficient for the average hobby athlete. Because the only fundamental difference between a non-athlete and an athlete is that the athlete needs a little more food and more fluid overall. So if you plan to do sport, you shouldn't worry too much about the ideal nutrient intake. He should just get started.

Prof. Dr. Dr. Christine Graf, born in 1967, heads the department for physical activity and health promotion at the German Sport University in Cologne. Above all, she deals with the influence of leisure activities on physical fitness and the negative consequences of a lack of exercise in children and adolescents.

The video reveals how much sport is really necessary to get fit