Before stepping on stage for a physique competition, there is usually a prolonged dieting phase = “contest prep”
The primary goal of this phase is to reduce body fat while maintaining muscle mass.
Contest prep phases can be short, maybe two months in length with weight loss as fast as 4 pounds (1.8 kg) per week with energy intakes reduced to minimal levels (less than 900 kcal/day). Rapid weight loss has been correlated with binge eating, amenorrhea, and other negative effects of dieting, such as excessive losses of fat free mass.
A more conservative and more drawn out approach to contest prep hypothetically sustains muscle mass to a greater degree.
Research surrounding physique sports has been picking up in recent years, but is still sorely lacking. Despite recent case studies tracking male bodybuilders throughout contest prep, there are far fewer reports on females.
The study subject was a 24 y white female. The participant began the five month study measuring 171.5 cm (5′ 7.5″), 67.4 kg (148 pounds), and 30.5% body fat. She had competed in two separate shows two years prior to this prep and placed fourth and fifth at those competitions. Training history included weight training 4-5 times per week for five years.
A comprehensive blood draw was taken, as well as other physiological measurements such as body composition, energy expenditure, and performance measures to determine changes caused by the preparation period on the subject.
Diet at the beginning of contest prep: 150g Protein, 305g Carbohydrate, 70g Fat + two refeed days consisting of 135g Protein, 415g Carbohydrate, 60g Fat – weekly average of 2500 kcal/day.
Diet at the end of contest prep: 150g Protein, 70g Carbohydrate, 70g Fat + refeed every five days consisting of 135g Protein, 300g Carbohydrate, 25g Fat – weekly average of 1460 kcal/day.
The subject was also taking daily supplements of creatine monohydrate (5 g/day), fish oil (3 g/day), and multivitamin. No birth control or prescription medications.
Body weight, nutrition, training, and menstrual cycle (which can cause weight fluctuations) were tracked.
Testing was done every four weeks including a blood draw, resting heart rate, blood pressure, resting metabolic rate, and underwater weighing (to determine body composition) in a fasted state. After a meal was consumed, the participant answered a mood questionnaire and completed performance testing.
Lipid, metabolic, and hormonal panels were run on the blood samples. Lipid: total cholesterol (TC), HDL cholesterol, triglycerides (TG). Metabolic: glucose, blood urea nitrogen (BUN), creatinine, BUN/creatinine ratio, sodium, potassium, chloride, carbon dioxide, calcium. Hormonal: thyroid stimulating hormone (TSH), leptin, estradiol (primary female sex hormone), cortisol, testosterone.
Mood evaluation was assessed on energy, tension, tiredness, and calmness subscales.
Training involved five weight training sessions per week – targeting each muscle group twice (one heavy day and one moderate day). Cardiorespiratory (cardio) sessions were increased in both frequency and duration as contest prep progressed. Participant was doing no cardio in the two months prior to beginning prep. At the time of competition cardio totaled 185 minutes of moderate intensity steady state and three 12-minute high intensity interval training sessions per week.
Highlighted changes during competition prep were:
- small fluctuations in fat free mass and resting metabolic rate
- strong weekly linear weight loss
- decline in energy intake of 1,040 kcal/day
- menstruation remained consistent for the first 4 months of the prep and was delayed during months 5 and 6
Aerobic fitness remained consistent.
Lipid panel was largely unaffected.
Metabolic panel was also unaffected. Thyroid stimulating hormone was initial high (above the reference range) but returned to normal ranges.
Hormonal panel values of estradiol and leptin were affected. Estradiol was elevated the last two months of prep – which can be seen with the delayed menstrual cycles. Leptin slowly dropped throughout testing until leveling out the last two months. Leptin is typically referred to as the “satiety hormone” and can serve as a marker for body fat reserves because it is produced by the body’s adipose (fat) cells.
Mood was relatively unaffected until month 5. Months 5 and 6 each had a decline in energy and an increase in tiredness. Change in energy had an inverse relationship with change in tiredness.
Weight was lost in a consistently linear fashion throughout contest prep. The participant lost half of her initial body fat while maintaining fat free mass. A high protein diet and a moderate rate of weight loss could explain body fat loss without accompanied fat free mass loss.
Small changes in resting metabolic rate (RMR) were observed despite the large drop in both calories (1040 kcal/day) and body weight (22.2 pounds). RMR decreased modestly (160 kcal) suggesting some adaptive thermogenesis occurred, possibly due to decreased body fat. Fat free mass was unaffected and RMR decreased by 10% while losing 15% of initial body weight.
Estradiol was low as menstruation began 1-3 days prior to monthly blood testing with the exception of the last two months in which menstruation was delayed and occurred after testing, thus elevating estradiol at time of testing. Cortisol and testosterone fluctuated but did not have any discernible trend upwards or downwards. Leptin substantially decreased. Decreases in leptin follow the drops in calories, which would be expected as decreases in leptin occur during caloric restricted periods.
Notably, mood was unaffected until the final 2 months of testing. Energy and calmness decreased and tiredness and tension increased suggesting that, despite changes in body fat percentage, calories, and training amount, mood may not be affected until a certain threshold of leanness is reached.
The results of the present study suggest that female athletes looking to improve body composition or reduce weight for improvement in sport performance could experience fewer physiological and psychological disturbances with a prolonged dieting period.
Based on the data from this study, the diet of the athlete should be consistent with a high protein intake to preserve fat free mass.