Timing and metabolic state of feeding effect on weight - Fasting, insulin, calorie deficit or surplus


People are on both sides of these topics. I’m searching for studies on things I’ve always wondered, but I believe still remains unclear in the fitness space.

  • Fasting:

It is my belief that the benefits of fasting for most people is a smaller feeding window manipulates appetite, and sticking to lower calories is much easier. Some say keeping insulin low is a huge part of weight being lost. I’m looking for more studies showing fasting - alternate day fasting, extended fasts, or traditional everyday fasts vs. every day calorie deficit, with all calories equal.

Regarding this, you have diet approaches such as the “Metabolic Blowtorch diet” which is essentially alternate day fasting - fasting 36 hours, and eating to satiety during the feeding window. My small N1 experience is if I fast an entire day, then consume 2,000 calories the next day, my weight ends up lower as opposed to the scenario where I consume 1,000 calories both days. This could be only in the short term, as I haven’t experimented with both scenarios a ton. Is this a case of low insulin and increased fat oxidation, or something that would all be equal in the long run?

  • Calories absorbed

Similar to the above, I wonder the difference between the effect of someone having one day of a huge caloric surplus vs. the effect of having that same surplus, spread throughout the week. Let’s person 1 has a 7000 calorie surplus in one day vs. person 2 has an extra 1000 calories all 7 days of the week. All activity the same, how would their results differ?

Some people say not all calories are absorbed if all consumed at once, some say for sure every calorie is absorbed. My guess would be somewhere in the middle. I believe if your glycogen is depleted going into the massive caloric surplus, you may see less of a fat gain, as around 2000 calories of glycogen cold be targeted first vs. if you were eating carby treats daily, your glycogen would be full the entire week, and more fat storage would occur. This is my theory, and I’ve heard some suggest this. I’m looking for more studies on this.

Of course there are other variables. Gone are the days where people believe they need to slam a protein shake seconds after exercising. However, protein synthesis, EPOC, and glycogen depletion certainly are a thing, and I believe impact weight gain/loss.

You have other diets like this. such as “The Cycle Diet” where one is in a deficit 6 days of the week, and splurges on calories on the 1 other day. My N1 experience with this is also limited. I’m typically an all or nothing in the sense that I’m either eating no cake or an entire cake. I’ve found that following a day like this with an extended fast typically gets me back to where I was, in a few days. I feel mainly because the calories get balanced out after fasting a couple days, but potentially all the calories are not absorbed?

Anyway, any studies or topics on any of the above, please share!

(Bacon by any other name would taste just as great.) #2

This makes sense, since restricted caloric intake acts as a signal to the body to conserve resources until the famine is over. Alternating feasting and fasting, however, seems not to have the same effect.

Eating to satiety avoids the whole problem. One study I read showed that while caloric intake and energy expenditure rarely matched on a day-to-day basis, over any given seven- or eight-day period, the match was extremely precise. Note that this is by eating to satiety, not by eating to a targeted number of calories. Note that we seem to have evolved to thrive on a pattern of feasting and fasting.

Judging food intake by how much energy would be yielded if the food were burnt in a calorimeter is a holdover from the days when calories were all we could measure. Calories from protein are traditionally always included in dietary calculations, even though we now know that protein is not generally metabolised, being reserved for structural uses instead.

Personally, I think we should really start considering food intake based on how much ATP will be yielded, under the dietary conditions obtaining at the time of the meal. By which I mean that, at some point during a famine, the body will start to metabolise protein in priority over fat, so as to conserve the fat store for later in the process of starvation. By the time the fat is all gone, the end is very close. Under such conditions, the metabolic contribution of protein is relevant, but not under more normal conditions.

Protein synthesis is done by taking amino acids from the labile pool. The capacity of the pool is limited, however, which is one of the reasons we need protein every day. (The other reason is that some small amount of amino acids is inevitably deaminated, both to produce glucose—under low-carb dietary conditions, anyway—and to liberate nitrogen to make NO for regulating blood pressure.) Glycogen depletion is of concern only when explosive muscle effort is required, and there are indications that the liver stores glycogen for sharing out to muscle as needed. Muscle glycogen is trapped in the muscle, but apparently liver glycogen is not trapped in the liver.

('Jackie P') #3