Exercise is beneficial to all people and an exercise programme should be complemented with a balanced diet.

Sometimes, certain adjustments need to be made to diet for people who have special preferences, needs or challenges. Certain health problems that occur as a result of exercise, such as gut problems and chronic fatigue, can also be curbed by eating correctly

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Vegetarian athletes
The biggest dietary concern facing vegetarian, lacto-vegetarian, vegan and fruitarian athletes is that they might not consume enough protein. Protein from plant foods, with the exception of soya and tofu, lack some essential amino acids.

The quality of the protein can be improved by combining vegetable proteins that complement each other. For example, a vegetable protein food that contains a good supply of essential amino acids, but lacks in one or two others, should be combined with vegetables that supply the missing ones.

The fat that vegetarians consume are generally poly- and monounsaturated and thus better alternatives to saturated animal fats. Poly- and monounsaturated fats are found n nuts, seeds, cheese and certain processed soya products.

When diary is excluded from the diet, it is more difficult to achieve adequate intakes of calcium, vitamin D and B12. Soya milk and breakfast cereals may provide these nutrients, but it is also advised that vegans take a vitamin B12-supplement.

Gut Problems
Gut problems during exercise can occur as a result of physical trauma, dehydration, and changes in stress hormones, which decease blood flow, disturb movement of the bowel and alter movement and absorption of food in the gut.

To prevent nausea and vomiting, it is recommended that before exercise, you eat low-fat, low-fiber, easily-digestible meals and snacks. Heartburn can be avoided by not eating highly concentrated carbohydrate beverages. Rather sip small volumes of drinks regularly. To avoid abdominal cramps, consume a low-fibre and low-residue diet before exercise and avoid lactose-containing foods and drinks before exercise. Eat a low-fibre, low-residue diet to avoid diarrhoea and eat something high in soluble fibre, like bran or oats.

Diabetes Mellitus
People with Type 1 and Type 2 diabetes can benefit from exercise, provided blood glucose levels are controlled. Exercise increases glucose uptake by the muscles, thereby helping to lower blood glucose levels. Exercise will also improve the sensitivity of the body to insulin. It helps to reduce body fat and reduces the risk of diabetic complications.

Your training diet should include carbohydrate-rich foods which are compatible with diabetic management. Consistent training and eating routines promote good diabetes management, so it is best to exercise at the same time each day in order to fine-tune your regime.

It is critical that you monitor your blood glucose levels regularly to assist in the adjustment of food and insulin to prevent and manage hyper- and hypoglycaemia.

To prevent hypoglycaemia (low blood glucose levels), avoid exercising during periods of peak insulin activity. If using shot-acting insulin, inject in the abdomen rather than the exercising limb to reduce the dose in necessary. To prevent late hypoglycaemia after exercise, you may need to reduce the next insulin dose. A further risk associated with hypoglycaemia is impaired temperature regulation, so adequate hydration is essential for optimum performance. Alcohol may mask the symptoms of hypoglycaemia.

Hyperglycaemia (high blood sugar levels) can be caused by infection, the overconsumption of food or highly concentrated sports drinks (usually for fear of the onset of hypoglycaemia), inadequate insulin and, in some cases, alcohol consumption.

Disabilities
The daily energy expenditure of athletes with disabilities can be as much as 30% lower when confined to a wheelchair. Energy intake will need to be adjusted accordingly and the focus should be on nutrient-dense foods low in fat and sugar.

If mobility is limited, constipation is very common. Dietary fibre intake together with adequate fluid and frequent meals are important to help regulate bowel movements.

It is important to be familiar with the potential side effects of medications that are frequently used as they may affect dietary movements.

When exercising in the heat, active cooling (in the shade), spraying with water and applying cooling devices may be needed. In cold environments, active heating and heat-loss prevention may be needed.

Chronic Fatigue
The symptoms of chronic fatigue include:

• fatigue and unexpected sense of effort during training
• frequent minor infections
• unexplained or unusually stiff and/or sore muscles
• mood disturbances
• changes in expected sleep quality and patterns
• loss of energy
• loss of competitive drive
• loss of libido
• loss of appetite
• excessive sweating

To diagnose chronic fatigue in athletes, other medical conditions need to be excluded, so it is best a sports physician or dietician be consulted.

Nutrition has great potential in the prevention and treatment of chronic fatigue. Undereating and low body mass is commonly seen in athletes with chronic fatigue. People who do not eat enough do not get all the macro- and micronutrients they need. Athletes with poor energy intakes frequently have poor vitamin and mineral intakes. Furthermore, chronic low energy intakes alter hormone such as leptin, which regulates body weight, metabolism and reproductive system, and thyroid hormones, which affect development, growth and metabolism.

If inadequate carbohydrate is consumed, repeated days of training can lead to depletion of the muscle glycogen stores and fatigue. Carbohydrate has also been shown to have several immune-protective benefits and reduce central fatigue.

Inadequate protein intake can lead to iron and zinc deficiencies which, over time, will suppress immune function and increase the susceptibility to opportunistic infections. Combining some protein with carbohydrate in the post-exercise period helps to build muscle and hastens recovery.

High-volume training may result in chronic elevations of serotonin levels, which suppress appetite and cause sleepiness.

Both high and low fat in the diet may affect immune function. Athletes with high-carbohydrate or high-protein diets may have a poor intake of minerals such as zinc, iron and selenium

Strenuous physical exercise induces oxidative stress, which may overwhelm the body’s antioxidant defence system. These defences include the antioxidant vitamins C and E and thiol antioxidants. There is evidence that antioxidant supplementation can help.
 

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