You go to the gym four days a week and never miss a session. Yet months have passed and your weights are not going up, your muscles are not becoming more defined or the scales will not move. Your energy runs out halfway through the session, and the next day your muscles are so sore that you cannot climb the stairs. The problem is usually not in the training but on the plate that feeds it.
Sports nutrition is not a subject for professional athletes alone. Anyone who regularly does fitness training, pilates, running, swimming, cycling or team sports needs to eat differently from someone who is inactive. On this page you will find which fuel the body uses during exercise, what to eat before and after training, how nutrition is adjusted for muscle gain and fat loss, and what supplements actually do.
Who is sports nutrition for?
- People who train with weights at the gym and want to increase their muscle mass
- People who aim to lower their body fat through exercise
- People who do endurance sports such as running, cycling, swimming and triathlon, and those preparing for a race
- People who do pilates, yoga and functional training
- People who take part in team sports and combat sports, whether licensed or amateur
- People who are new to exercise and want to build the right habits from the start
Which fuel does the body use during exercise?
Muscles run on two main fuels: carbohydrate and fat. Carbohydrate is stored in the muscles and liver as glycogen; it is a store that can be used quickly but is limited. Fat stores, on the other hand, are very large, but turning them into energy is slower.
As the intensity of exercise rises, the share of carbohydrate grows. In low-intensity activities such as brisk walking, fat takes the lead; in interval training, heavy sets or fast running, the body relies mainly on glycogen. When glycogen stores run out, the legs feel heavy, the pace drops and it becomes harder to concentrate. Protein, rather than being a fuel, is used to repair and rebuild the muscle fibres worn by training.
The cost of eating little and training a lot
Many people who want quick results do two things at once: they cut their food and increase their training. In the first weeks the scales go down; then the picture reverses. When the energy taken in stays too low for the energy used over a long period, the body switches to saving mode. The signs are these:
- Tiredness that does not pass and a fall in training performance
- Frequent injuries, slow recovery, falling ill often
- Disturbed sleep, irritability, loss of motivation
- In women, irregular periods or periods stopping altogether
- In the long term, reduced bone density
- Weight loss coming to a halt, loss of muscle
This is the situation often seen in women who cannot lose weight despite exercising very hard: the problem is not eating too much, but eating too little and at the wrong times. The solution is not to train even more, but to put energy intake and rest in order.
Carbohydrate, protein and fat: how much and when?
Carbohydrate
Carbohydrate is the fuel of training. The requirement varies with the length, intensity and weekly frequency of training. Someone who exercises lightly three days a week and a runner preparing for a marathon do not have the same carbohydrate needs. In people who cut carbohydrate too far, the quality of training falls; in the long term this harms both performance and body composition. Bulgur, oats, wholegrain bread, potatoes, rice, pasta, pulses and fruit are the main sources.
Protein
People who train regularly need more protein than those who are inactive; it is generally set within a range of 1.2–2 grams per kilogram of body weight per day, according to the goal and the training load. Distribution matters as much as the total: spreading protein across the day’s meals supports muscle repair better than loading it into a single meal. Eggs, dairy products, meat, chicken, fish and pulses are good sources. In people with kidney disease, the amount of protein is decided in consultation with the doctor.
Fat
Fat is needed for hormone production and for absorbing fat-soluble vitamins. In people who cut fat too far, especially women, hormonal balance can be disturbed. Olive oil, nuts, avocado and oily fish are preferred; fat is kept low only in the meal just before training, because it slows digestion.
What should you eat before training?
The purpose of the meal before training is to fill the stores and to avoid stomach discomfort during the session.
- Two to three hours before: A main meal containing carbohydrate and protein, with moderate fat and fibre. For example, bulgur pilaf with chicken and yoghurt, or a sandwich with egg and cheese.
- Half an hour to an hour before: If a long time has passed since the main meal, a small snack that is easy to digest: a banana, two or three dates, or a bowl of yoghurt with fruit.
- Early morning training: If your stomach can take it, a small source of carbohydrate is enough; setting out with nothing at all before hard or long sessions lowers performance.
Which food sits well, and how long beforehand, varies from person to person; that is why the timing is adjusted by trying it out on training days.
What should you eat after training?
After training the body has two jobs: refilling the emptied glycogen stores and repairing the muscle fibres. This calls for a meal that contains carbohydrate and protein together. Oats with yoghurt and fruit, wholegrain bread with eggs, a main dish with meat or pulses served with rice, or ayran with a cheese sandwich are suitable examples.
The belief that your effort will be wasted unless you take protein the moment training ends is exaggerated. For most people, eating a balanced meal within a few hours of training is enough. What really decides the outcome is the day’s total intake of protein and energy. Skipping the meal after a late evening session because “it’s too late”, however, delays recovery.
Fluid and electrolyte balance
Losing fluid equal to even a small percentage of body weight lowers performance and concentration. You need to avoid starting training short of fluid, drink water at intervals during the session and replace what was lost afterwards. Urine that is a pale straw colour is a practical sign that you are drinking enough.
For sessions shorter than an hour, water is enough. In training done in the heat of an İzmir summer, lasting more than an hour or involving heavy sweating, the sodium lost in sweat also needs to be replaced; in that case ayran, mineral water or a suitable sports drink can be used. In long-distance races, drinking more water than needed can also create danger by lowering sodium in the blood; the fluid plan is made to suit the event.
Nutrition according to your goal
Muscle gain
Building muscle needs three conditions together: regular resistance training that challenges the muscle, energy slightly above your needs and enough protein. Gaining muscle while in an energy deficit is very difficult. Sleep matters at least as much as nutrition; muscle repair takes place largely during sleep.
Fat loss
If the goal is to lower body fat, the energy deficit is kept moderate, protein is raised and enough carbohydrate is left to protect the quality of training. In this way the weight lost comes from fat and muscle is preserved. For the general principles of the process, see the weight management page.
Endurance sports
In disciplines such as distance running, cycling and triathlon, carbohydrate needs are high. Carbohydrate loading is planned in the days before events lasting more than ninety minutes, and regular carbohydrate and fluid intake during the event. The basic rule is this: on race day, no food, drink or gel is used that has not been tried in training.
Supplements: protein powder, creatine, BCAA and caffeine
- Protein powder: Not a medicine or a muscle builder, but a concentrated food. If you can get enough protein from meals during the day, you do not need it; if you cannot, it is a practical solution.
- Creatine: One of the most researched supplements; it can support performance in short, high-intensity efforts. The small rise seen on the scales at the start comes from water held inside the muscle, not from an increase in fat. It can be used by women too. People with kidney disease should not use it without consulting a doctor. We cover the subject in detail in the article on creatine for women.
- BCAA: It has not been shown to give any extra benefit to someone who already gets enough protein.
- Caffeine: A moderate amount before training can reduce perceived fatigue; too much causes palpitations, restlessness and disturbed sleep.
- Fat burners and products with unclear contents: Not recommended. They may contain substances not listed on the label, carry health risks and lead to a doping violation in licensed athletes.
A supplement is a small detail added on top of a sound eating pattern; it does not make up for irregular eating. Before using one, consult your dietitian and, if you have a health problem, your doctor.
Common nutrition mistakes made by people who exercise
- Going to training hungry and thirsty: Performance falls and the risk of injury rises.
- Being afraid of carbohydrate: Cutting off the fuel of training makes the training itself unproductive.
- Squeezing protein in only after training: Protein spread through the day is more effective.
- Turning training into a reward: Eating more than was used because “I exercised today” is a common trap.
- Relying on supplements and neglecting meals: No product takes the place of regular meals.
- Leaving rest and sleep out of the reckoning: Progress is made not in training but during recovery.
- Copying someone else’s programme: The plate of an athlete seen on social media was prepared for that person’s training load.
Frequently asked questions
Does exercising on an empty stomach burn more fat?
In exercise done on an empty stomach, the share of fat burned at that moment may rise; but what determines total fat loss by the end of the day is the day’s energy balance. People whose performance drops or who feel dizzy when training fasted are better off having a small meal first.
Is it essential to use protein powder?
No. If you can meet your daily protein needs from meals, there is no need. It is a convenience for people who work long hours and have no chance to eat between meals.
I train late in the evening. Should I eat afterwards?
Yes. A meal after training is needed for recovery. Late in the evening, a meal that is easy to digest, contains protein and is moderate in portion is preferred.
I exercise regularly but cannot lose weight. Why?
Possible reasons include overestimating the energy used in training, increased appetite after training, too little sleep and muscle gain hiding the drop on the scales. Looking at body composition analysis and circumference measurements instead of the scales gives more accurate information.
I have just started exercising. Do I need to change my diet straight away?
Big changes are not needed. Starting with regular meals, protein at every meal, the right timing around training and enough water is sufficient; the details are added as the training load increases.
