Weightlifter’s Diet

Nikos Skiadas
Hellenic Weightlifting Federation General Secretary, Greece

Recent studies have shown that the diet of an athlete is a very important factor in his/her performance and good training conditions. The diet of the athlete has two purposes, first to cover caloric and nutrient needs and secondary to maintain fluid balance in the body. Situations and conditions specific to sport training and sport participation often make meeting these objectives difficult.

To provide nutritional information to athletes in the context of real recommendations, physicians have to consider not only the science behind the nutritional requirements but also the athlete’s lifestyle, training program, preferences, and factors specific to the sport.

Most of the studies for sport nutrition have been conducted on subjects participating in aerobic activities of long duration. Since the majority of the athletic events are anaerobic and require sudden bursts of effort separated by periods of relative rest, such as weightlifting, the widely published and often repeated guidelines may not be the best recommendations for athletes participating in anaerobic sports.

Energy Requirements

Energy requirements depend on body size, period of training, training conditions, age, and non-training activity level, with body size being the primary determinant. There is a wide range of energy intakes when comparing athletes participating in the same sport because the intake depends on body weight. The intake limits are from 28-kcal/ kg body weight to 65-kcal/ kg body weight depending on the sport, although some athletes have been reported to need 12,000 kcal per day.

Some competitive sports require adherence to rigid weight standards. Athletes who participate in these sports must closely monitor their weight and thus their caloric intake. Too often this leads to nutritional abuses, dehydration, and serious health risks. In addition, the dietary tactics used by some athletes to achieve excessive weight loss are of increasing concern because of the potential association with eating disorders, such as anorexia nervosa and bulimia nervosa.

The athlete’s diet should contain a relative balance of carbohydrate, fat, and protein. Of the total calories consumed, the recommended balance for most athletes is:

• Carbohydrate - 55% to 60%
• Fat - no more than 30% (less than 10% saturated)
• Protein - 10% to 15%

Although all foods can ultimately be broken down to carbohydrate, fat, or protein, these nutrients are not all that the body needs.

Without a metabolic chamber it is difficult, if not impossible, to determine calorie requirements of an athlete accurately due to day-to-day, season-to-season and athlete-to-athlete variation. A practical rule to determine the requirements is to check the body weight of the athlete. If the body weight is stable, the athlete’s energy intake is equal to the energy output. It is desirable to have the athlete record everything consumed for 3 consecutive days. The results of this record should give an estimate of energy requirements in the presence of a stable body weight. A simple rule to determine energy needs is to multiply the athlete’s body weight by one of the following numbers:

After determining, multiply the number by 2.2. For example, a male athlete with a body weight of 95kg and a heavy activity level needs 4807 kcal (95kg X 23 = 2185, 2185 X 2.2 = 4807 kcal)

Nutrient Requirements

A. Carbohydrate

Most research conducted on carbohydrate requirements has examined runners and cyclists in laboratory settings. Data from these studies have been extrapolated to athletes in other sports because no better data currently exists. As more applicable data becomes available, current recommendations may change. Research indicates athletes training or competing at high intensities (>70% V0max) for prolonged periods of time have a high carbohydrate requirement. Athletes, whose training and competitions consist of brief periods of high-energy output, alternated with short periods of rest, such as sprinters, weightlifters, and football players, have lower carbohydrate requirements.

The body stores excess carbohydrate, primarily in the muscles and liver, as glycogen. Because of this, carbohydrate consumption directly influences muscle glycogen storage and the ability to train and compete in endurance events. The athletes who train intensely and eat a low-carbohydrate diet (40% of total calories) often experience a day-to-day decrease in muscle glycogen. When these athletes consume a high-carbohydrate diet (70% of total calories), their muscle glycogen levels recover almost completely within 22 hours of the training bouts. In addition, athletes are able to train more efficiently when their muscle glycogen is maintained throughout a workout.

Early studies have reported that when men eat a diet containing a normal amount of carbohydrate (about 55% of total calories ingested) their muscles store about 100 mmol of glycogen per kg of muscle. One study showed that diets containing less than 15% carbohydrate led to storage of only 53 mmol kg-1, but rich carbohydrate diets (60% to 70% carbohydrate) led to storage of 205 mmol kg-1. When subjects exercised to exhaustion at 75% of their maximal oxygen uptake, their exercise times were proportional to the amount of muscle glycogen stored before the test.

More recent studies have shown that glycogen storage replacement is not simply determined by carbohydrate intake. Exercise with an eccentric component, such as running and weightlifting, can induce some muscle damage and impair glycogen re-synthesis. In these situations, muscle glycogen levels can appear quite normal during the first 6 to 12 hours after exercise, but glycogen re-synthesis slows or stops completely as muscle repair begins.

To replace the liver glycogen we need 200g/day. Athletes training aerobically (> 90 minutes per day) need 8-10g/kg of body weight to maintain muscle glycogen levels. Five g/kg of body weight per day is adequate to support training of athletes involved in intermittent, power, or sprint activities.

B. Protein

Research shows that athletes have increased protein requirements compared to their sedentary counterparts. Protein is a classified as a nitrogen-containing compound formed by amino acids. Protein serves numerous functions in athletes’ body:

• It is the major structural component of the cell
• It is used for growth, repair, and maintenance of body tissues
• Hemoglobin, enzymes, and many hormones are produced from it
• Normal blood osmotic pressure is maintained by proteins in the plasma
• Antibodies for disease protection are formed from it
• Energy can be produced from it

The average diet adequately meets the protein needs of the athlete. Theoretically, protein needs for heavy physical training should be met, even when energy expenditure exceeds 5,000 kcal per day. This is assuming that the proportion of protein in total energy consumed is maintained. Studies with college men revealed that those who engaged in a month of weight training and followed diets containing either 0.8 g or 2. 4 g of protein per kg of body weight each day retained more protein than a group of men who followed the same diet but did not train. Nitrogen excretion in urine, an indicator of protein use, decreased significantly in the training group. The weight-trained men retained enough protein for a 2 kg increase in fat-free body mass. Comparing the need for protein and the gains in fat-free body mass suggested that the intake of only 0.8 g of protein per kg of body weight per day might have been low. Instead, the higher intake of 2.4 g might have better met the subjects’ protein needs. In another study, two groups of men consumed different amounts of protein (1.4 g and 2.8 g per kg body weight per day) during a prolonged period of intense physical training. Only the group on the high protein diet significantly increased fat-free body mass. During the early stages and heavy periods of training, some endurance athletes may need as much as 1.6 g of protein per kg of body weight each day. For strength training, research findings are still unclear, though most researchers agree that an intake of 0.9 g per kg of body weight per day might be adequate for those who are simply maintaining their muscle mass.

The factors that increase athlete’s protein requirements are:

1. Low calorie diet: An important factor affecting protein requirements is the interrelationship of protein and energy. Increasing energy intake improves nitrogen balance. Thus, protein requirements increase as energy intake decreases.

2. Vegetarianism: Digestibility and ammo acid composition of vegetable protein are not equal to animal protein, leading to increased requirements.

3. Endurance training: Utilization of protein as an energy source increases during endurance activities and the amount used depended on glycogen stores or carbohydrate consumption.

4. Resistance training: Resistance training and the resulting muscular hypertrophy increase protein requirements. The increased need varies with degree of effort and phase of training period.

5. High muscle-to-fat ratio

6. Growth

The protein requirements for an endurance training athlete is 0.9 t0 1.4 g / kg body weight per day and for a strength training athlete is up to 1.8 g / kg body weight per day, but generally the athletes use 1.5 to 2.0 g /kg body weight per day.

C. Fat

Fat is a class of organic compounds with limited water solubility. It exists in the body in many forms, such as triglycerides, free fatty acids, phospholipids, and sterols. The body stores fat primarily as triglycerides, composed of three molecules of fatty acids and one molecule of glycerol. Triglycerides are our most concentrated source of energy. It functions as a carrier of fat-soluble vitamins, adds palatability to the diet, and has a protein-sparing effect. An important role of fats is in their role of fatty acid oxidation in sparing glycogen stores. We must mention that trained athletes oxidize more fat and less carbohydrate than untrained and that exercise performed under aerobic conditions promotes fat oxidation.

Fat serves many vital functions in the body:

• It is an essential component of cell membranes and nerve fibers.
• It is a primary energy source, providing up to 70% of total energy in the resting state.
• Vital organs are supported and cushioned by it.
• All steroid hormones in the body are produced from cholesterol.
• Fat-soluble vitamins gain entry into and are transported through the body via fat.
• The insulating subcutaneous fat layer preserves body heat.

For the athletes, fat is especially important as an energy source. Muscle and liver glycogen stores in the body are limited; therefore, the use of fat (free fatty acids), for energy production can delay exhaustion. Clearly, any change that allows the body to use more fat would be an advantage, particularly for endurance performance. In fact, one adaptation that occurs in response to endurance training is an increased ability to use fat as an energy source. Unfortunately, merely eating fat does not stimulate the muscles to burn fat. Instead, eating fatty foods only tends to elevate plasma triglycerides, which must then he broken down before the free fatty acids can be used for energy production. To increase the use of fat, the free fatty acids levels in the blood, not the triglycerides levels, must be increased.

D. Vitamins

Vitamins are a group of unrelated organic compounds that perform specific functions to promote growth and maintain health. We need them in relatively small quantities, but without them we could not utilize the other nutrients the athletes ingest. Intakes above requirements have not been shown to improve performance in the absence of deficiency. The fat-soluble vitamins, A, D, E, and K, are absorbed from the digestive tract along with and bound to lipids. The B-Complex vitamins and vitamin C are water-soluble. They are absorbed from the digestive tract along with water. Any excess of these vitamins is excreted, mostly in the urine, but vitamin toxicity has been reported with some of these. Because of the role of vitamin B in energy producing metabolic processes, athletes with high-energy expenditure may have increased requirements.

E. Minerals

A comprehensive review of minerals is not warranted. Iron and calcium, however, are frequently consumed in amounts less than required and therefore deserve further discussion.

1. Iron: As a component of hemoglobin, myoglobin, and cytochromes, iron impacts oxygen transport and energy metabolism. Although anemia appears to be no more common in athletes than in nonathletic persons, low iron stores are a frequent finding among elite endurance athletes. Iron deficient anemia affects performance by decreasing the capacity of skeletal muscle to consume oxygen and produce ATP. The athletes should be informed about the types and sources of dietary iron to prevent or augment treatment of iron depletion or deficiency.

2. Calcium: Calcium is important to bone health, in combination with gonadal hormones and physical activity, but does not compensate for either. For example, in female athlete with decreased estrogens levels, calcium supplementation does not prevent bone loss. It is important to note that if an athlete takes calcium and iron supplements at the same time, the absorption of iron is decreased significantly. Therefore, if iron supplements are used, calcium supplements should be taken apart from them.

Fluid Balance

For optimal performance, the body’s water and electrolyte contents should remain relatively constant. Unfortunately, this doesn’t always happen during exercise. To keep the fluid balance in normal levels the athletes can drink water or carbohydrate-electrolyte replacement beverages. These beverages are isotonic drinks and promoted as a source of carbohydrates and electrolytes. The carbohydrate solutions containing < 11% carbohydrates from a mix of glucose, fructose, glucose polymers or sucrose are absorbed quickly and used to maintain blood glucose and hydration status. The electrolyte solutions are not physiologically necessary for electrolyte replacement in most cases because the majority of the athletes consume adequate electrolytes from their diet. Electrolyte solutions are necessary in cases when an athlete is not fed normally; for example, when he loses weight. The use of such drinks should be tested during training and not consumed for the first time during competitions.

The Precompetition Meal

The primary purpose of this meal is to provide fluid and energy to the athlete during the competitions. Numerous recommendations on timing, amount, and types of food for pre-competition meals appear in sports nutrition publications. Many of the recommendations are not supported by scientific data and may not be appropriate for all athletes. For years, athletes have received the traditional steak before competition. This practice might have originated from the early belief that muscle consumes itself to fuel its own activity, and that steak would provide the necessary protein to counteract this loss. This is a myth because we know that steak is probably the worst food an athlete could eat prior to competing. Steak contains a high percentage of fat, which requires several hours for full digestion; during competition, the digestive system would compete with the muscles for the available blood supply. Also, nervous tension is typically high before a big competition, so even the choicest steak cannot truly be enjoyed at this time. The steak would be more satisfying, and less likely to disturb performance, if the athlete eats it either the night before or after the competition.

Although the meal ingested a few hours before competition might contribute little to muscle glycogen stores, it can insure a normal blood glucose level and prevent hunger. This meal should contain only about 200 to 500 kcal and consist mostly of carbohydrate foods that are easily digested. Foods such as cereal, juice, and toast are digested rather quickly and won’t leave the athlete feeling full during competition. The rates at which food is digested and nutrients are absorbed into the body are quite individualized, so timing the pre-competition meal might depend on prior experience.

Generally the athlete must avoid eating fat because fat slows gastric emptying. Liquid meals can replace conventional foods, and while suitable in any situation, may be of particular value in situations of limited availability of food and with athletes who have cut weight. It is important to notice that the athletes must take food and beverages that are liked, are well tolerated, and are usually eaten. Finally, we can advice that the pre-competition meal should be individualized.

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