When a low-carb diet works for me, what is it that's actually working?

Benjamin T. BikmanPhD · Professor of Cell Biology and Physiology, Brigham Young University; director of the Laboratory of Obesity and Metabolism

The insulin. Lower it and the fat cell releases

What it rests onCell-level signalling. Fat cells enlarging by hypertrophy become insulin resistant, leak fatty acids and drive ectopic fat into liver, pancreas and muscle; the disruptors of insulin signalling there are diacylglycerols and ceramides rather than triglyceride, which is why endurance athletes carry muscle triglyceride without insulin resistance. He calls the result insulin toxicity rather than energy toxicity.

Layne NortonPhD · nutrition scientist, coach, and competitive powerlifter

The calorie deficit, which the diet made easier to hold

What it rests onIsocaloric feeding comparisons and the observation that weight is lost on GLP-1 medication and in other settings where insulin is not low. He addresses Bikman by name, in an episode with a chapter titled 'Dr. Bikman's Claims', characterising the position as 'if we keep insulin low and control seed oils, fat cells can stay smaller and healthier' and arguing the hyperplasia and hypertrophy story does not carry the weight put on it.