I guess everyone knows about this pre-print
A plant-based, low-fat diet decreases ad libitum energy intake compared to an animal-based, ketogenic diet: An inpatient randomized controlled trial
There is a wealth of data to enjoy and a lot to say from the Protons and insulin point of view but just a brief look gives us equal weight loss, equal fat loss and the sort of changes in fat free mass you would expect from likely shifts in glycogen and its associated water:
Clearly the extra 600kcal eaten under ketogenic conditions did nothing to blunt fat loss, much as we would expect from the low carb perspective. The extra calories did not evaporate, they were lost through increased energy expenditure, especially during sleep and while sedentary:
These people have uncoupled metabolism during the period of eating the ketogenic diet, they generate heat. As measured within the limits of indirect calorimetry. You could argue about a greater faecal, urinary or breath mediated loss of calories too but that's less important than a measured equivalent weight loss despite higher, extremely accurately measured caloric intake.
That's all pretty boring.
What is really, really interesting is the equivalent spontaneous weight loss under the period of high carbohydrate intake. Over the years I've looked at the carbosis vs ketosis for potential mechanisms and this study may go some way to clarifying what is going on. The very low fat eating certainly does not limit the penetration of either glucose nor insulin past the liver. Both spike systemically after every meal. But still there is spontaneous weight loss due to a suppressed appetite.
Under low fat eating less "waste" heat is generated, metabolism is coupled. Tightly coupled metabolism means people needed less calories. The subjects, under very low fat eating, lost weight without any biochemical markers of inadequate calories. Just as they did under ketogenic eating.
That's really interesting. With data, lots of it including important things like the effect of a typical meal on blood glucose, insulin and lactate. Plenty to work with. Needs a lot of thinking about.
BTW does this sound like a metabolic advantage to ketogenic eating? Rhetorical question, 24h energy expenditure combined with utterly accurate food intake measurements tells us something...