Many people state that minimizing carbs is the only dietary requirement to increase use of body fat as energy (PSMF, for example). Others claim that you must eat a reasonable amount of fat to teach/stimulate/allow/optimize/whatever the body to utilize fat most effectively (regressive keto, for example).
Does anyone know of any studies that show one method works better than the other?
The point of a PSMF is not to "minimize carbs". A PSMF is a PROTEIN SPARING MODIFIED FAST. The purpose of it is to minimize FOOD, not simply carbs.
And no, Easy Rhino is correct. You cannot tell your body to burn more fat by eating more fat. At maintenance, your body will burn calories it's normal rate, the type of which will be proportionate to the ratio of energy substrate consume (in this scenario calories/macros in = calories/macros out). Of course, in a deficit, the extra energy requirement will be comprised of fat, glycogen, and some glucose via gluconeogenesis (so calories out = calories/macros in + free fatty acids, glycogen, etc).
What happens to proteins or carbs? Are you saying fat does not get digested and broken down? Fat stays a fatty acid throughout the entire process? Not trying to be a dick just curious to hear this. I always assumed whatever someone ate got broken down and if it wasn't used then it would be turned into fat.
And I apologize because in my lazy/unorganized response I forgot to finish with my point, which was that a high fat diet, still in caloric balance, will show increased fat oxidation and increased fat storage at the same time, with the net amount stored staying about the same.
Fats are completely digested down to free fatty acids, then reconstructed again as triglycerides for storage. Your body does not store olive oil fats or beef fats, it stores human-specific fats. This is not a zero energy process, but neither is the breakdown of proteins to amino acids or the various carbohydrates to sugars. The fat pathways are much less efficient, but probably not to the extent that the metabolic effect is significant.
What is significant is that fat and protein take longer to break down and get to the cells, so they don't cause systemic spikes of macronutrients; this allows your body to apportion nutrients as it needs, rather than as a response to abnormal levels. This is the primary benefit of lowered carb diets, that your body doesn't have to spike insulin because it sees a sugar level it doesn't like. Your body also doesn't have to store fat- if you don't believe me, drink a cup of olive oil and report back; too much sugar that your body can't absorb will have the same effect, like what happens with the lactose intolerant.
I think that this is the justification for recommendations to eat protein and carbs or protein and fats, but not all three together in significant quantities or carbs and fats together, because of the storage effects. I think that more fat ingested as part of a low carb diet will end up utilized as energy before being stored.
I'm sure you don't actually mean this, but the order in which you've written your information at least IMPLIES that low insulin has something to do with more fat being burned. And I'm almost positive that has nothing to do with it.
A low carb diet generally means lower glycogen stores, and the lower your glycogen stores, the greater proportion of fats are burned for energy. The higher the glycogen stores, the more of the energy required for physical activity will come from glycogen.
Yes, I'm aware I wrote "low insulin" and then "low carb" in the next paragraph. That's what I mean: you started talking about insulin and then jump to low carb (nothing wrong with the jump) but the flow of information implies the association I'm talking about.
Of course, it depends on what type activity you're doing, but again I think you forgot to mention that more fat being burned on a low carb diet is due to lower average glycogen stores, not less insulin spikes. At least, that's what your text implied (or what I felt it implied).
For the record, I still don't believe in the P+F, P+C nonsense. I think the merits to constructing meals like that come from the (partially) unintended effect of consuming more carbs PWO, where they would likely be more beneficial in that timeframe. I say unintended because the original prescription was based on controlling insulin, which I think has been way over dramatized.
Because if you recall, Berardi would say to eat P+C PWO and P+F at other times. That doesn't necessarily mean that eating C and F (with P) would result in more F being stored due to the insulin spiking of C.
Also, insulin spiking changes when a meal has multiple macros and when the amount of macros change. A meal high in C might not spike insulin as high if there's a lot of F and fiber in the meal.
Correct. The whole point of a PSMF is to reduce food intake to the point that all your left with is the least amount of caloris from the RIGHT sources without causing dysfunction in health or performance (although you can't perform much exercise with one). So all your left with is protein, EFA's, and veggies.
Rhino's right. The macro stored as fat when above maintenance calories is fat.
There is no one better method. People have gotten cut to ribbons with ketogenic diets and high carb (50-60%) diets. It depends on personal preference and what the person responds better to. The most important thing in losing fat is a caloric deficit.
I don't know of any studies offhand.
You don't "teach" the body really. If you go on a high carb or high fat diet, then somehow get the chance of visiting an exercise physiology lab in which they conduct respiratory gas analysis, you'll see that the respiratory quotient shows what you're burning as fuel. High carb diet = more carbs burned for fuel. High fat diet = more fat burned for fuel. It's that simple--no teaching.