So Gary Taubes’ organization, NuSI, helped fund a study by Dr. Yoni Feedhoff (which was also funded by the NIH).
They had 19 individuals on a carefully controlled diet, at a fixed calorie level, go through a baseline diet with normal carbs, and then a low-carb diet with 5% carbs for a month (in total, a 2-month study.) They had repeated 24-hour metabolic ward habitations during the study in order to watch their change in energy expenditure and their oxidation rates as they shifted from normal metabolism to ketosis. They measured fat levels with DXA.
Basically, this expensive study went with the gold standards for measurement accuracy on everything.
Most interesting (to me) findings:
During the 15 days on the “baseline” normal diet with carbs, the subjects were already losing fat - even though they were supposedly eating the same “normal” number of calories they ate previously! This is just another example of how people are nearly always eating more than they think; and when they’re forced to eat only how much they thought they were eating, they often lose weight and lose fat.
During the subsequent 30 days on the low-carb diet, the subjects lost only as much fat as they lost in the first 15 days. In other words, fat loss slower while eating low-carb, even though eating the exact same number of calories and getting the exact same amount of activity. (They did have a jolt of rapid non-fat weight loss at the beginning of the transition, as the body’s protein burning went up before the body could become adequately fat-adapted, but for the rest of the thirty days, fat loss was slower than while previously eating carbs.)
They conclude there’s no metabolic advantage to a low-carb diet, and that that the insulin hypothesis proves invalid as regards metabolism and fat storage / fat bruning. (But that there’s some interesting help on the appetite management side.)
Worth a listen.