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Unfortunately I can only summarize. On the starvation study it's merely one example that highlights how calorie restriction affects people. Yes, it's an extrem

• wdewind 10y ago
  > On the starvation study it's merely one example that highlights how calorie restriction affects people. Yes, it's an extreme version, but it is different only in degree from any other calorie restriction, and when people try to reduce by X calories, it's probably a linear effect; more restriction, more of these effects. Oddly though, fasting tends not to have these effects, it's only in sustained calorie restriction, so fasting in various forms is one of the tools people can use to lose weight. No dude, you are ignoring the fact that these people did not have ample fat stores. It is completely unreasonable to expect that obese people would behave the same while restricting calories than people who are already borderline starving (4% BF). These aren't effects of caloric intake restriction, they are effects of caloric restriction in general, which is a state obese people are not, have not been in for years and will not be in for years. > One major problem is that the basal metabolic rate does not stay stable. Decreased caloric intake can decrease basal metabolic rate by up to 40 percent This is basically unrelated to your statements about insulin though, so don't conflate the two. This statement does not support the idea that obese people cannot harvest energy from their fat stores, it supports the idea that you get less energy output from less energy input which is almost tautologically true.
  • buzzcut 10y ago
    > "No dude, you are ignoring the fact that these people did not have ample fat stores." I don't think I am ignoring it. You seem to be asserting that their issues with calorie restriction were lack of body fat. There is no evidence for that I am aware of. A simple rejoinder based on anyone's experience, do fat people get hungry? If they do, why? They have all that energy available. But I don't need to rely on arguments like that, since in the vast corpus of research on this at this point, it's pretty well established that calorie restriction by itself (even with exercise) does not work long-term. The failure rate is astronomical and it is in part due to what plain old calorie restriction as we've been told to do it does to metabolic energy and also due to the psychology of hunger. Also, and this is very important, a full fast does not have these effects according to the evidence. People can totally abstain from food for very long periods of time (depending on body fat), with very little hunger. It is smaller scale calorie reductions, without breaks (like the breaks intermittent fasting provides) and without much dietary fat since fat is highly satiating, that cause these reactions to calorie restriction. > "This is basically unrelated to your statements about insulin though, so don't conflate the two." Again, I'm not. I was responding to the request for a source on the idea of energy output reduction in response to lower calories. I'm not claiming there is a link between energy output reduction and insulin. Fat people can get energy from fat stores, just not in the way we are typically told. If it was impossible to get energy from fat no one would ever lose weight, which is trivially and obviously not true.
    • wdewind 10y ago
      > You seem to be asserting that their issues with calorie restriction were lack of body fat. No I'm asserting that what happens to people's bodies at 4% body fat when in severe caloric restriction is very different than what happens to people's bodies at 40% body fat with severe caloric restriction, and so we can't apply the metabolic damage/starvation models to fat people. Fat people just need to eat less, and the issue basically comes down to compliance. How do we get people to stay on a healthy diet long term? > do fat people get hungry? If they do, why? Because, as even you have shown, hunger is not a reflection of your bodies actual caloric needs, it's hugely a reflection of blood sugar levels, among other htings. Given enough time (in the order of magnitude of minutes to hours) in an obese but otherwise healthy person fats will be broken down and blood glucose will increase and hunger will decrease. It's getting through that period that is a mental compliance issue, but not otherwise physiologically challenging. > The failure rate is astronomical Again, this is a compliance issue. People absolutely lose weight on caloric restriction, and starvation issues like low metabolism do not become an issue until you are very low body fat. You simply do not see obese people going into so-called "starvation mode." In fact there are a few cases, though admittedly not many, of obese people that abstain entirely from eating for months at a time without long term "metabolic damage." > People can totally abstain from food for very long periods of time (depending on body fat), with very little hunger. I think we basically agree, then, that it's mostly a compliance issue and not an issue of caloric restriction working or not, and also that hunger is not a reflection of the body's actual metabolic state (especially in obese people). > Fat people can get energy from fat stores, just not in the way we are typically told. Fat people get energy from fat stores in the same way skinny people do. Very skinny people on severe caloric restriction are not a good model for the general population.