4 ms·

"don't eat, lose weight" is obvious of course. "eat the same amount of calories but with different timing, lose weight" is more interesting. Does having higher

"don't eat, lose weight" is obvious of course. "eat the same amount of calories but with different timing, lose weight" is more interesting. Does having higher growth hormone levels result in burning more calories with the same amount of physical activity?

arcticbull 6y ago
Based on what I've read so far, and again, I'm not an expert, just sort of an arm-chair enthusiast. 1. One major component to weight gain is insulin. Insulin triggers the uptake of blood glucose by your adipocytes, and prevents its release. This means when your insulin is high, your body stores free sugar as fat and prevents your body from releasing it for consumption. 2. Insulin follows a positive feedback cycle and can exhibit a runaway condition, broadly speaking, called insulin resistance. You eat more sugar, your body produces more insulin, your cells get used to the insulin, and your body has to produce more insulin to lower your blood sugar. 3. Eventually your body can't make more insulin. It's tapped out. So your doctor prescribes you, usually, a front-line treatment like Metformin -- itself fascinating in its own right as a life extension drug. Once that's not sufficient to control your blood sugar, you have to start start injecting insulin. This is broadly speaking Type II diabetes and, eventually, metabolic syndrome. 4. The idea with intermittent fasting, or adjusting the timing of your meals, is that your body does in fact lower its insulin level once you stop eating. That much we know. Over time, longer periods in this low-insulin state this will reduce your body's concept of what a "low" insulin level is, walking back that runaway condition. 5. In time, this might reverse Type II diabetes [1]. The linked writeup is a small study, n=3, however: "All three men were able to stop injecting themselves with insulin within a month of starting their fasting schedule. In one case this took only five days." 6. Once insulin levels are normal, you're back to normal, too. HGH reduces body fat and increases lean muscle mass. [2] Further, when fasting, your metabolism is actually elevated, in part due to high levels of noradrenalin. Makes sense, if you're an ape in the jungle and you haven't eaten in a day or so, your body is primed to go out and get more food -- not to waste away. So, lots of moving pieces, and we're not 100% sure yet. There appears to be smoke here, IMO, which is why I mentioned I'm just excited to see any studies at all. [1] https://www.bmj.com/company/newsroom/planned-intermittent-fasting-may-help-reverse-type-2-diabetes-suggest-doctors/ https://www.bmj.com/company/newsroom/planned-intermittent-fa... [2] https://www.acpjournals.org/doi/10.7326/0003-4819-152-9-201005040-00007 https://www.acpjournals.org/doi/10.7326/0003-4819-152-9-2010...
- mikevm 6y ago
  Insulin is not the only hormone responsible for storing fat, Acylation Stimulating Protein (ASP) is produced by adipocytes and also stimulates fat storage. There's nothing really special about IF for fat loss, muscle gain, or for reducing insulin resistance. Improved insulin sensitivity is a natural result of fat loss. Here's a study on diabetics that are put on a 2200 kcal diet with 400grams of carbs: https://pubmed.ncbi.nlm.nih.gov/21483296/ https://pubmed.ncbi.nlm.nih.gov/21483296/ There was a 10% weight loss, and their HbA1 levels (average blood sugar) returned to pre-diabetic levels (they could essentially stop insulin injections). The increase in HGH levels that happens during a fast is not a net anabolic event, but a compensatory anti-starvation response that shifts fuel substrate use from glucose and amino acids toward lipolysis and ketone production. Part of the cause of GH release is reduced hepatic IGF-1 production, resulting in less negative feedback to the pituitary gland to produce GH. So during a fast you end up with more GH, but less IGF-1. IGF-1 is more directly active[0] in skeletal muscle in producing growth than HGH. Basically, the result is that while fasting-induced GH secretion does help counteract muscle protein breakdown, it does little to increase muscle protein synthesis when you're fasted and you remain in negative whole-body protein-balance. There is nothing anabolic about not eating, as your body has no fuel for new protein synthesis. It's also only a matter of time before you start losing muscle. Muscle protein breakdown rates starts in between 15-30 hrs of fasting[1]. Fasting for 20 hrs decreases resting energy expenditure[2] and mTOR signaling, an important component of anabolic gene expression. This suggests that 20+ hour fasts may negatively affect you muscle mass and fat loss. GH also drives insulin resistance[3], so more growth hormone isn't always desirable. All in all, given some limited studies we have on IF, IF per se does not provide body recomposition advantages and does not alter energy expenditure, and fasts over 20 hours are even harmful. Any health benefits of IF are highly inconsistent and mostly limited to glucose and insulin dynamics. Being lean is much more important for our health than whether you do IF or not. Being muscular probably is too, because muscle mass improves insulin sensitivity. Combined with being lean, any benefits for insulin sensitivity of IF are arguably trivial for muscular, exercising individuals. I could give you a bunch more studies here, but I think this is enough for now :). Having said all that, you can still use calorie cycling strategies to reduce caloric intake on "rest days" (or more precisely, outside of your anabolic windows) by using a PSMF (protein-sparing modified fast), and upping your caloric intake during anabolic windows (which could last up to 72 hours after training!). [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2439518/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2439518/ [1] https://pubmed.ncbi.nlm.nih.gov/6476111/ https://pubmed.ncbi.nlm.nih.gov/6476111/ [2] https://academic.oup.com/ajcn/article/90/5/1244/4598111 https://academic.oup.com/ajcn/article/90/5/1244/4598111 [3] https://www.sciencedirect.com/science/article/abs/pii/S1096637405000201 https://www.sciencedirect.com/science/article/abs/pii/S10966...
PeterisP 6y ago
For many types of diet that focus not directly on calories but on the selection, timing or form of eating, the intent that you do not eat the same amount of calories, but rather that eating a "natural amount" according to your appetite within the "new habits" will result in you eating less calories without explicitly measuring and limiting these calories.

arcticbull 6y ago

Based on what I've read so far, and again, I'm not an expert, just sort of an arm-chair enthusiast. 1. One major component to weight gain is insulin. Insulin triggers the uptake of blood glucose by your adipocytes, and prevents its release. This means when your insulin is high, your body stores free sugar as fat and prevents your body from releasing it for consumption. 2. Insulin follows a positive feedback cycle and can exhibit a runaway condition, broadly speaking, called insulin resistance. You eat more sugar, your body produces more insulin, your cells get used to the insulin, and your body has to produce more insulin to lower your blood sugar. 3. Eventually your body can't make more insulin. It's tapped out. So your doctor prescribes you, usually, a front-line treatment like Metformin -- itself fascinating in its own right as a life extension drug. Once that's not sufficient to control your blood sugar, you have to start start injecting insulin. This is broadly speaking Type II diabetes and, eventually, metabolic syndrome. 4. The idea with intermittent fasting, or adjusting the timing of your meals, is that your body does in fact lower its insulin level once you stop eating. That much we know. Over time, longer periods in this low-insulin state this will reduce your body's concept of what a "low" insulin level is, walking back that runaway condition. 5. In time, this might reverse Type II diabetes [1]. The linked writeup is a small study, n=3, however: "All three men were able to stop injecting themselves with insulin within a month of starting their fasting schedule. In one case this took only five days." 6. Once insulin levels are normal, you're back to normal, too. HGH reduces body fat and increases lean muscle mass. [2] Further, when fasting, your metabolism is actually elevated, in part due to high levels of noradrenalin. Makes sense, if you're an ape in the jungle and you haven't eaten in a day or so, your body is primed to go out and get more food -- not to waste away. So, lots of moving pieces, and we're not 100% sure yet. There appears to be smoke here, IMO, which is why I mentioned I'm just excited to see any studies at all. [1] https://www.bmj.com/company/newsroom/planned-intermittent-fasting-may-help-reverse-type-2-diabetes-suggest-doctors/ https://www.bmj.com/company/newsroom/planned-intermittent-fa... [2] https://www.acpjournals.org/doi/10.7326/0003-4819-152-9-201005040-00007 https://www.acpjournals.org/doi/10.7326/0003-4819-152-9-2010...

mikevm 6y ago
Insulin is not the only hormone responsible for storing fat, Acylation Stimulating Protein (ASP) is produced by adipocytes and also stimulates fat storage. There's nothing really special about IF for fat loss, muscle gain, or for reducing insulin resistance. Improved insulin sensitivity is a natural result of fat loss. Here's a study on diabetics that are put on a 2200 kcal diet with 400grams of carbs: https://pubmed.ncbi.nlm.nih.gov/21483296/ https://pubmed.ncbi.nlm.nih.gov/21483296/ There was a 10% weight loss, and their HbA1 levels (average blood sugar) returned to pre-diabetic levels (they could essentially stop insulin injections). The increase in HGH levels that happens during a fast is not a net anabolic event, but a compensatory anti-starvation response that shifts fuel substrate use from glucose and amino acids toward lipolysis and ketone production. Part of the cause of GH release is reduced hepatic IGF-1 production, resulting in less negative feedback to the pituitary gland to produce GH. So during a fast you end up with more GH, but less IGF-1. IGF-1 is more directly active[0] in skeletal muscle in producing growth than HGH. Basically, the result is that while fasting-induced GH secretion does help counteract muscle protein breakdown, it does little to increase muscle protein synthesis when you're fasted and you remain in negative whole-body protein-balance. There is nothing anabolic about not eating, as your body has no fuel for new protein synthesis. It's also only a matter of time before you start losing muscle. Muscle protein breakdown rates starts in between 15-30 hrs of fasting[1]. Fasting for 20 hrs decreases resting energy expenditure[2] and mTOR signaling, an important component of anabolic gene expression. This suggests that 20+ hour fasts may negatively affect you muscle mass and fat loss. GH also drives insulin resistance[3], so more growth hormone isn't always desirable. All in all, given some limited studies we have on IF, IF per se does not provide body recomposition advantages and does not alter energy expenditure, and fasts over 20 hours are even harmful. Any health benefits of IF are highly inconsistent and mostly limited to glucose and insulin dynamics. Being lean is much more important for our health than whether you do IF or not. Being muscular probably is too, because muscle mass improves insulin sensitivity. Combined with being lean, any benefits for insulin sensitivity of IF are arguably trivial for muscular, exercising individuals. I could give you a bunch more studies here, but I think this is enough for now :). Having said all that, you can still use calorie cycling strategies to reduce caloric intake on "rest days" (or more precisely, outside of your anabolic windows) by using a PSMF (protein-sparing modified fast), and upping your caloric intake during anabolic windows (which could last up to 72 hours after training!). [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2439518/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2439518/ [1] https://pubmed.ncbi.nlm.nih.gov/6476111/ https://pubmed.ncbi.nlm.nih.gov/6476111/ [2] https://academic.oup.com/ajcn/article/90/5/1244/4598111 https://academic.oup.com/ajcn/article/90/5/1244/4598111 [3] https://www.sciencedirect.com/science/article/abs/pii/S1096637405000201 https://www.sciencedirect.com/science/article/abs/pii/S10966...

PeterisP 6y ago

For many types of diet that focus not directly on calories but on the selection, timing or form of eating, the intent that you do not eat the same amount of calories, but rather that eating a "natural amount" according to your appetite within the "new habits" will result in you eating less calories without explicitly measuring and limiting these calories.