King Grub
2015-04-15, 13:32
Objectives
Weight loss (WL) is associated with a decrease in total and resting energy expenditure (EE). We aimed to investigate whether 1) diets with different rate and extent of WL determined different changes in total and resting EE and if 2) they influenced the level of adaptive thermogenesis, defined as the decline in total or resting EE not accounted by changes in body composition.
Methods
Three groups of six, obese men participated in a total fast for 6 days to achieve a 5%WL and a very low calorie (VLCD, 2.5 MJ/day) for 3 weeks or a low calorie (LCD, 5.2 MJ/day) diet for 6 weeks to achieve a 10%WL. A four-component model was used to measure body composition. Indirect calorimetry was used to measure resting EE. Total EE was measured by doubly labelled water (VLCD, LCD) and 24-hr whole-body calorimetry (fasting).
Results
VLCD and LCD showed a similar degree of metabolic adaptation for total EE (VLCD = -6.2%; LCD = -6.8%). Metabolic adaptation for resting EE was greater in the LCD (-0.4 MJ/day, -5.3%) compared to the VLCD (-0.1 MJ/day, -1.4%) group. Resting EE did not decrease after short-term fasting and no evidence of adaptive thermogenesis (+0.4 MJ/day) was found after 5%WL. The rate of WL was inversely associated with changes in resting EE (n = 30, r = 0.-42, p = 0.01).
The fraction of FFM to total WL after 5%WL was 46, 30 and 18% for the fasting, VLCD and LCD groups respectively. At 10% WL, the VLCD losses were 20% FFM and 80% FM compared with 9% FFM and 91% FM in the LCD group.
Conclusions
The rate of WL did not appear to influence the decline in total EE in obese men after 10%WL. Approximately 6% of this decline in total EE was explained by mechanisms of adaptive thermogenesis.
Imposed rate and extent of weight loss in obese men and adaptive changes in resting and total energy expenditure. Metabolism 2015.
http://www.metabolismjournal.com/article/S0026-0495(15)00104-3/fulltext
Weight loss (WL) is associated with a decrease in total and resting energy expenditure (EE). We aimed to investigate whether 1) diets with different rate and extent of WL determined different changes in total and resting EE and if 2) they influenced the level of adaptive thermogenesis, defined as the decline in total or resting EE not accounted by changes in body composition.
Methods
Three groups of six, obese men participated in a total fast for 6 days to achieve a 5%WL and a very low calorie (VLCD, 2.5 MJ/day) for 3 weeks or a low calorie (LCD, 5.2 MJ/day) diet for 6 weeks to achieve a 10%WL. A four-component model was used to measure body composition. Indirect calorimetry was used to measure resting EE. Total EE was measured by doubly labelled water (VLCD, LCD) and 24-hr whole-body calorimetry (fasting).
Results
VLCD and LCD showed a similar degree of metabolic adaptation for total EE (VLCD = -6.2%; LCD = -6.8%). Metabolic adaptation for resting EE was greater in the LCD (-0.4 MJ/day, -5.3%) compared to the VLCD (-0.1 MJ/day, -1.4%) group. Resting EE did not decrease after short-term fasting and no evidence of adaptive thermogenesis (+0.4 MJ/day) was found after 5%WL. The rate of WL was inversely associated with changes in resting EE (n = 30, r = 0.-42, p = 0.01).
The fraction of FFM to total WL after 5%WL was 46, 30 and 18% for the fasting, VLCD and LCD groups respectively. At 10% WL, the VLCD losses were 20% FFM and 80% FM compared with 9% FFM and 91% FM in the LCD group.
Conclusions
The rate of WL did not appear to influence the decline in total EE in obese men after 10%WL. Approximately 6% of this decline in total EE was explained by mechanisms of adaptive thermogenesis.
Imposed rate and extent of weight loss in obese men and adaptive changes in resting and total energy expenditure. Metabolism 2015.
http://www.metabolismjournal.com/article/S0026-0495(15)00104-3/fulltext