CLINICAL KNOWLEDGE MAGAZINE
5 min read
Initial Nutritional Intervention Preparation
Kacper Nowak
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Diets Premium Medical Expert • 25.03.2026
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Scientifically reviewed by a clinical dietitian:
This article has been peer-reviewed for adherence to IŻŻ, WHO, and PTGiP clinical nutritional standards.
| CLINICAL KNOWLEDGE MAGAZINE CLINICAL KNOWLEDGE MAGAZINE | min read 5 min |
| Diets Premium Medical Expert Kacper Nowak | Scientifically reviewed by a clinical dietitian 25.03.2026 |
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Key Takeaways
Nutritional strategies implemented before, during, and after activity should consider numerous objectives. They should provide energy, support established goals and physical capabilities by considering various factors related to nutrition and fatigue. These may include dehydration, low blood glucose levels, depletion of glycogen reserves, electrolyte imbalance, discomfort arising from the digestive system (nausea, bloating, hunger sensation). Furthermore, they should have a health-promoting effect and enhance the ability to perform further exercises during sports tournaments lasting for several days.
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Pre-launch nutritional preparation
Nutritional strategies based on the earlier preparation for the start rely on several factors, including: sporting events, environmental conditions, individual preferences, appetite, food tastes and rules applicable during competitions. Start preparation should begin a few weeks before the start of the event by introducing snacks during the activity and trying out a meal before the race. Nutritional strategies that appear a few days before the event should be based on increased availability of carbohydrates for optimal performance. The time for carbohydrate loading depends on the duration of the event. For activities lasting less than 90 minutes, the increased dose of carbohydrates, i.e. 7-12 g/kg body weight, should be introduced the day before. For sports lasting longer than 90 minutes or interrupted sports (e.g. football), carbohydrate loading can be considered 36-48 hours before the event. In this time, athletes should choose foods with a high carbohydrate content that are easy to consume, meet nutritional requirements and ensure gastrointestinal comfort, especially the day before the event.
Ingestion of meals during the execution of exercises
The introduction of meals during prolonged exercise sessions can maintain effort at the highest level of intensity. Any discomfort arising from improper functioning of the digestive system may affect the quality of the exercise performed. By introducing meals during exercises, we can train the digestive system - reduce the feeling of discomfort. Regular consumption of meals during physical activity improves absorption and emptying of the stomach. Such an approach allows us to prepare the body for performance and ensures that no unpleasant situation occurs during runs or competitions. Individuals with high sensitivity of the digestive system should begin consuming meals in small portions (15 g/h) and gradually increase them to achieve the desired effect – and adjust them to the intensity and type of competition.
Provision of fluids during physical exertion
Most physically active individuals commence their workouts with an inadequate level of hydration, which can have a negative impact on their performance. To prevent this, it is recommended to provide 5-10 ml of fluid per kg of body weight 2-4 hours before starting the workout. The primary objective is to maintain hydration and avoid dehydration below 2% body weight. It is estimated that a fluid loss of 0.3 to 2.4 liters per hour can occur during training. It is also essential to perform routine measurements of body weight before and after training to determine the required fluid volume during long-term exercise. Most athletes consume 0.4 to 0.8 liters of fluid per hour, but this amount should be individually adjusted to environmental conditions, sweating rate, type of sport, and duration and intensity of training.
Nutritional strategies prior to launch day
Pre-launch day nutritional strategies should be based on easily digestible, well-tolerated foods. On this day, it is advisable to avoid hard-to-digest, fatty, and spicy products and a high amount of caffeine. It is permissible to consume steamed, low-fat, grilled foods. If there is a tendency to stomach and intestinal problems during exercise, the amount of fiber should be reduced. It is also recommended to eliminate dairy products due to lactose (sugar), such as cottage cheese, milk, yogurt. It is suggested to replace them with plant-based beverages: rice, almonds. It is advisable to focus on carbohydrates: buckwheat, basmati rice, potatoes, rice pasta, durum pasta, graham bread, wheat bread. Useful vegetables in this diet are: carrot, beetroot, pumpkin, zucchini, vegetables from broth, tomatoes (without skin); and fruits: bananas, oranges, kiwi, watermelon, melon. Recommended protein sources are: fish, eggs, meat (chicken breast, turkey breast, beef, rabbit). It is also recommended to use herbs: thyme, basil, marjoram, chives.
Preventing Hypoglycemia - Methods to Aid You
Studies conducted in the 1970s demonstrated that carbohydrate intake per hour before exercise resulted in substantial increases in blood glucose and insulin levels 45 minutes after ingestion. Upon initiating physical exertion, a significant decrease in blood glucose levels was observed due to the combined effect of high insulin levels and exercise, as well as intensified glucose metabolism. Blood glucose levels dropped so drastically that hypoglycemia developed in some individuals. This condition is often referred to as reactive hypoglycemia and presents itself with symptoms such as weakness, nausea, and dizziness. Symptoms of hypoglycemia occurred only in some individuals, which aligns with the views of some athletes who claim to be more sensitive to carbohydrates than others who never experience symptoms of hypoglycemia. In practice, this means that they can consume carbohydrates before exercise, as they do not have any detrimental effects on activity. Each person is unique, and therefore every athlete must develop their own pre-workout eating habits - they adapt them to their needs. Individuals prone to reactive hypoglycemia can consider several solutions: avoiding carbohydrates one hour before exercise, consuming carbohydrates (CHO) 5 minutes before performance (gels, gummies, bars, drinks), and limiting CHO portions to 60g per hour before performance.
Kacper Nowak
Diets Premium Medical Expert
Member of the Diets Premium clinical editorial board. Specializes in medical diet therapy, metabolic health, and nutritional planning.
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