Thanks for taking the time, jsbrook. I’m going to respond to a couple of your points to further illustrate my confusion.
Throughout most of our history, food was scarce. So, the body breaks down muscle first when there’s an excessive deficit to save essential fat stores. Muscle is a very metabolically costly tissue, and the body doesn’t really want more.
See, this is the very crux of what I’m not understanding. Why would the body break down muscle first in order to preserve fat stores? The very reason for having fat stores is to use as energy when food is scarce! The body obviously had a reason for BUILDING that muscle in the first place, so why would it then break down the muscle (which has negative survival implications in and of itself) in order to SAVE the FAT?!?!? Burn the damn fat! That’s why you stored it in the first place! Conserving fat at the expense of muscle tissue is the very antithesis of a survival response. The result is you’re left with a heavier body (which requires more calories to move around), and less muscle with which to move that flab (and run from predators, chase food, etc.). It’s completely counterintuitive.[/quote]
Sure. I’m no expert. But from my understanding of evolutionary anthropology, there was little surplus fat stores during most of our existence. Most of what we had on our bodies was reasonably close to essential fat. So, in times of famine, we would want to hold onto it and would catabolize some muscle. Some fat still was lost. Muscle is functional and helped us get our prey butis metabolically a costly tissue and was not all that helpful if there was no food available for it to help hunt or gather. But this is the body’s response in starvation-like circumstances.
A proper cutting diet isn’t analogous to this and shouldn’t induce this, and it hasn’t in my experience. 500-1000 calories below maintenence consisting of many smaller, protein-rich meals, coupled with weight-training (our ancestor’s definitley wouldn’t have been engaging in hard exercise in the absence of food)has resulted in minimal to zero muscle loss, at least for me.
If in a caloric deficit, the body will ultimately still lose fat (even though not necessarily as effectively) on a higher carb diet because all the carbs will ultimately be used for energy and maintence and fat stores must still be tapped into.
Okay, so the idea is that by eating more carbs, that just means there’s that much more carbs to burn off before tapping into fat, I guess? But replace those carbs with protein, and you still have a potential source of glucose, it just requires a bit more work to convert that protein (which I’m assuming accounts for the added thermogenic “cost” of protein consumption vs. fat, etc.). Assuming that you only ideally need 1.0 to 2.0g / kg / d of protein in order to grow, then is the only true benefit of going low carb the fact that you’re getting less actual glucose out of your food, since something like 70 to 75% of the calories represented by protein are actually available to the body once the protein is converted to glucose? Could you get the same effect by just eating carbs instead, but adjusting your intake to account for that differential? [/quote]
I suppose you could have a higher percentage of carbs and lower overall caloric intake. I’m not exactly sure of all the scientific aspects of it, to tell you the truth. But I’ve personally have better results in terms of body composition with a higher protein diet as a practical matter. This is even true for performance as an endurance athlete. I competed at a fairly high level. Finished with that, I’m training for mass for the first time. I have a very protein-heavy diet for this bulk now as well. Read The Proten Debate article if you haven’t already. I really liked it.
[quote]ChrisPowers wrote: Protein is more thermic than carbs and speeds up the metabolism.
Does protein really “speed up” the metabolism, or does it just require more calories to be digested and used as energy by the body (or for building tissue, or being stored as fat, etc.)? Does your body really say, “okay great, more protein, time to release more thyroid stimulating hormone and burn more calories for no reason”?
I don’t know exactly, but I think the body works harder to digest protein, so it burns more calories in doing so. Digestion is a part of metabolism.
I hope that Tampa Terry also responds. I’m sure she is more knowledgeable than I am and can give more scientific explanations. But I hope I was able to help some.