Key messages
The latest battle in the perpetual diet wars claimed that low carbohydrate diets offer a metabolic advantage to burn more calories and thereby help patients maintain lost weight.
However, analyzing the data according to the original pre-registered statistical plan resulted in no statistically significant effects of diet composition on energy expenditure.
The large reported diet effect on expenditure calculated using the revised analysis plan depended on data from subjects with excessive amounts of unaccounted energy. Adjusting the data to be commensurate with energy conservation resulted in a diet effect that was less than half the value reported in the BMJ paper.
The measured daily average CO2 production rates were not significantly different between the diets and the reported expenditure differences were due to inaccurate calculations based on false assumptions about diet adherence.
