Originally Posted by Derek Weaver
And unfortunately one that tends to work better for people already closer to their goals. People a little farther off need to be a bit more careful.
You're right though.... it's a lot of fun.
Frequency of those types of loading days will differ greatly between people with low BF (who can get away with more) vs people with higher BF%. But also....1 day of eating up does not crush a weight loss plan....as the body thinks in calorie load terms over days and weeks....not hours. Anyone can pig out one day and then ramp it back down to counteract it the following days. But the metabolic signals through refeeds may be the lacking part of someone who is plateauing with weight loss....especially if there is a history of more prolonged low cal/carb dieting.
Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects
OBJECTIVE: To determine the effects of excess carbohydrate or fat intake on plasma leptin concentrations and energy expenditure.
DESIGN: Ten healthy lean females were studied: (a) during a 3 day isoenergetic diet (ISO); (b) during 3 day carbohydrate overfeeding (CHO OF); and (c) during 3 day fat overfeeding (FAT OF). During each test, basal metabolic rate, the energy expended during mild physical activity and recovery, and 24 h energy expenditure (24 h EE) were measured with indirect calorimetry. The concentrations of glucose and lactate were monitored in subcutaneous interstitial fluid over a 24 h period using microdialysis. Plasma hormone and substrate concentrations were measured in a blood sample collected in the morning of the fourth day.
RESULTS: CHO OF increased plasma leptin concentrations by 28%, and 24 h EE by 7%. Basal metabolic rate and the energy expended during physical activity were not affected. FAT OF did not significantly change plasma leptin concentrations or energy expenditure. There was no relationship between changes in leptin concentrations and changes in energy expenditure, suggesting that leptin is not involved in the stimulation of energy metabolism during overfeeding. Interstitial subcutaneous glucose and lactate concentrations were not altered by CHO OF and FAT OF.
CONCLUSIONS: CHO OF, but not FAT OF, increases energy expenditure and leptin concentration.
Lyle has a relevant post on fat loss at higher bf% today as well:
T-nation actually has a good article on Leptin overview as well: http://www.t-nation.com/free_online_...ptin_manifesto