|Four Week High-Protein-Reduced Calorie Diet Improves Performance without Affecting Anabolic Hormones|
by: Robbie Durand
High protein diet have long been advocated for maintaining lean muscle mass while dieting. It is recommended that athletes gradually reduce their calories slowly while dieting because rapid loss can result in muscle mass loss. A recent study showed that rapid weight loss in sports such as wrestling (60%-90%). Another study reported a similar percentage in combat sports such as judo athletes (62.8%), jujitsu (56.8%), karate (70.8%), and taekwondo (63.3%). A recent review paper published in the Journal of Exercise in Sports Sciences Reviews titled, “The Ketogenic Diet and Sport: A Possible Marriage?” reports the benefits of a ketogenic diet in some sports, especially power sports requiring weight loss. The review paper talks about the biochemistry of ketogenic diets and how athletes often have to have a rapid weight loss for a competition. Some of the standard techniques used to make weight are: ‘crash’’ diets with extreme energy restriction, dehydration attempts, sauna suits, and use of pharmaceuticals such as diuretics. Biochemical, physiological, and observational studies also provide good evidence that an actual ketogenic diets (i.e., where adherence is checked) can lead to fat loss with little or no loss of muscle mass.
For one study, which has reported that compared with a standard ad libitum diet, a 30-day ketogenic diet did not affect explosive and strength performance negatively in a group of high-level gymnasts. In the study, nine elite male athletes from Italy were recruited and placed on a very low carbohydrate ketogenic diet. Tests included hanging leg raises, push ups, parallel bar dips, pull ups, squats jumps, countermovement jumps and 30 secs of continuous jumping. The athletes in the study average training volume was 30 hours/week. The diet provided was 54.8% fat, 40.7% protein and 4.5% carbohydrate with all vitamins and minerals accounted for to ensure proper nutrition. The modified ketogenic diet was mostly made up of beef, veal, poultry, fish, raw and cooked green vegetables without restriction, cold cuts (dried beef, carpaccio, and cured ham), eggs, and cheese (such as parmesan). The drinks allowed were infusion tea, moka coffee, and herbal extracts. The foods and drinks that athletes avoided on the ketogenic diet included alcohol, bread, pasta, rice, milk, yogurt, soluble tea, and barley coffee. However, comparison of measurements before and after the ketogenic diet shows a significant reduction in body weight, fat mass, and fat percentage, and an increase in lean body mass percentage. This indicates that many athletes concerned either about aesthetics or weight categories can use a properly controlled ketogenic diet and after adaptation, perform at their normal levels of function while losing weight through macronutrient manipulation.
The key point that the author made in the review paper is an energy sufficiency while with a very low carbohydrate intake, but this is compatible entirely with normal protein consumption and rich nutrition providing full complements of micronutrients and essential macronutrients. The ketogenic diet is used widely as a weight loss strategy and, more rarely, as therapy for some diseases. In many sports, weight control is often necessary (boxing, weightlifting, wrestling, etc.), but the ketogenic diet usually is not considered. The ketogenic diet might be used to achieve fat loss without affecting strength/power performance negatively.
|Slower is Better for Maintaining Muscle Mass|
The newest study published in the Journal of Strength and Conditioning Research reports that when dieting, a slow reduction in calories is best for maintaining muscle mass as opposed to a fast reduction in calories. Researchers examined the effects of a 4-week weight reduction period with high protein and reduced carbohydrate intake on body composition, explosive power, speed, serum hormones, and acid-base balance in male track and field jumpers and sprinters. Eight participants were assigned to:
– a high weight reduction group (energy restriction of 750 kcal day) and
– a low weight reduction group (energy restriction of 300 kcal per day).
Weight reduction gradually by 2 kg in 4 weeks was accompanied by improved weight-bearing vertical jumping and sprinting performance, without severe negative consequences on serum anabolic and catabolic hormones and lean mass. Explosive power and sprint running performance improved in high weight reduction loss group. Improvements in vertical jump height after weight reduction have also been noted in some previous studies.
Only a slight and loss of lean mass occurred in high weight reduction group. Protein intake was high (2 g/kg/day) in both groups before and during the weight reduction protocol. However, high protein intake (~2 grams per kg of bodyweight) during weight reduction seems to protect lean muscle, especially when energy restriction is more than 500 kcal per day.
Key Points: During low calorie diets, as long as high protein diets are maintained, explosive power can be maintained without a reduction in anabolic hormones. The study found that there were only small reductions in lean muscle mass, but a gradual reduction in calories is best for maintaining lean muscle mass.