Are short fasts really helpful for burning fat?

Christine_72 wrote: »

I lost the majority of my weight doing Alternate day Fasting.

Monday-500 calories
Tuesday-TDEE
Wednesday-500 calories
Thursday-TDEE and so on.

When i first started i found it easier to diet every second, rather than 7 days a week.

ETA: It was a 24 hour fast from dinner till dinner the next night.

stevencloser wrote: »

dykask wrote: »

stevencloser wrote: »

dykask wrote: »

rankinsect wrote: »

Well, the real thing is - it doesn't actually matter how much fat is burned at any particular instant in time, what matters is the long term effect over the course of days and months.

For that, the only thing that really affects total change in body fat is the total energy deficit or surplus over that period of time. Everything else would cancel out in the long term.

If only human bodies were that simple then losing fat would be easy! It is actually very difficult to determine even what type of weight has been lost let alone how much a energy deficit or surplus there is. Clearly people do lose fat but it isn't so easy as cutting 100 kc / day and lose 5 kg of fat / year.

That is why intermitted fasting is interesting. It may help the body actually more like expected by helping with hormones and keeping the metabolism from declining. At first I thought it was nonsense, but now I'm a lot more open minded about it.

It IS that simple. Glycogen depletion from high intensity exercise gets refilled by incoming carbs, creating a larger deficit during the times you're at rest -> burning fat. And muscle loss isn't an issue for anyone getting their nutritional needs and working out.

There are many variables and many possible outcomes but typically only about 5% are successful with losing fat and keeping it off. As for the glycogen depletion, very few people actually can actually burn so much glycogen that it can't be replaced from the food being consumed. It is really very difficult to just exercise yourself slim.

Intermittent fasting though would help a lot by helping making it easier to deplete more glycogen and providing periods where blood glucose and insulin are lower. People aren't successful with burning fat if insulin levels are too high. It is likely that most people are in that state most of the waking hours. If those people eat a calorie deficit they end up feeling horrible because the body reduces energy expenditure if it can burn enough fat.

The 5% number is taken from an amount of people they didn't even know if they were trying to lose in the first place.

Glycogen replacement is the reason you still lose fat even when you're doing strenuous exercise that "burns carbs not fat" which is the origin of those stupid fat burning zone workout *kittens*.
Carbs that are turned to glycogen to refill your tank aren't used to fuel your caloric needs, so you're burning bodyfat while refilling your glycogen because substrate utilization shifts to primarily fat while at rest.
Your glycogen does not have to be depleted to lose fat. Your insulin is lower if you're in a deficit anyway and the idea that you need to decrease insulin to lose fat is bunk to begin with.

Background: After weight loss, total energy expenditure—in particular, energy expenditure at low levels of physical activity—is lower than predicted by actual changes in body weight and composition. An important clinical issue is whether this reduction, which predisposes to weight regain, persists over time.

Objective: We aimed to determine whether this disproportionate reduction in energy expenditure persists in persons who have maintained a body-weight reduction of ≥10% for >1 y.

Design: Seven trios of sex- and weight-matched subjects were studied in an in-patient setting while receiving a weight-maintaining liquid formula diet of identical composition. Each trio consisted of a subject at usual weight (Wtinitial), a subject maintaining a weight reduction of ≥10% after recent (5–8 wk) completion of weight loss (Wtloss-recent), and a subject who had maintained a documented reduction in body weight of >10% for >1 y (Wtloss-sustained). Twenty-four-hour total energy expenditure (TEE) was assessed by precise titration of fed calories of a liquid formula diet necessary to maintain body weight. Resting energy expenditure (REE) and the thermic effect of feeding (TEF) were measured by indirect calorimetry. Nonresting energy expenditure (NREE) was calculated as NREE = TEE − (REE +TEF).

Results: TEE, NREE, and (to a lesser extent) REE were significantly lower in the Wtloss-sustained and Wtloss-recent groups than in the Wtinitial group. Differences from the Wtinitial group in energy expenditure were qualitatively and quantitatively similar after recent and sustained weight loss.

Conclusion: Declines in energy expenditure favoring the regain of lost weight persist well beyond the period of dynamic weight loss.

• (1) Doing Intermittent fasting and it helps
  
• --- Result building more fat than the deficit and the body raises metabolism to make up the difference! Yay!
• (2) CICO prediction
• --- Burn deficit in fat
• (3) Typical result
• --- Burn less than deficit in fat and the body reduces metabolism to make up the difference.
• (4) Sickly result
  
• --- No fat loss and the body reduces metabolism by the deficit amount. People feel sluggish, low energy, etc
• (5) Worse case result
  
• --- Fat is added and the metabolism is reduced by more than the deficit. Insulin resistance is high and increasing, next stop is probably type 2 diabetes. At this point a person has at least one foot in the grave.

lemurcat12 wrote: »

dykask wrote: »

lemurcat12 wrote: »

dykask wrote: »

I'm more interested in intermitted fasting as a way to bring the body back to a more healthy state.

If you are overweight and it helps you lose weight it will do that.

That goes along with the theory that excess fat storage is actually a protective mechanism to deal with too much insulin in the blood. High insulin causes fat to be stored, low insulin allows fat to be burned.

This doesn't make sense in the absence of a calorie surplus/deficit. You will burn more fat than you store with a calorie deficit (and not have enough consistent insulin or topped up glycogen stores to interfere with that). If you store more fat than you burn it's because you have eaten more calories than you need to fuel activity. Nothing else makes sense.

Also, if someone is IR, that means their body is LESS able to store fat than someone with normal insulin sensitivity. Their cells are resistant to insulin, which is why their body keeps making more and more. To blame insulin resistance for fatness, rather than excess calories and obesity for become IR (much more common, although there is an inherent genetic risk factor and not everyone obese gets IR or everyone IR is obese), seems like an excuse, a desire to believe that you gained weight for some reason besides overeating.

If hunger is an issue, trying things like keto and IF could help with that, of course.

I like the idea of IF for reasons unrelated to any physical effects (which I am skeptical about). I find it more satisfying to eat main meals and not snack or graze and I think the latter is too often encouraged and doesn't work well for many, whereas things like eating windows and ADF/5:2 might. I also think experimenting with partial fasts or low cal days can be educational. I've never had trouble running on a 12-hour fast (which I don't personally consider a fast), but I do have issues so far exercising hard a on low cal day (500 cal).

In addition to experimenting with IF, I've experimented with mostly plant-based diets, including ways of eating that are much higher carb than what I normally fall into (my default seems to be 40% carbs). I have not found at all that I am tempted to eat more on this higher carb way of eating or gain weight -- quite the opposite. (But I like meat, eggs, and dairy, so...)

You have it backwards with insulin resistance and fat storage. If you are IR it means your body is producing a lot more insulin to overcome the resistance. That high insulin will force glucose into the cells and that increases fat storage. The high levels of insulin a take longer to clear out of the blood preventing fat from being burned. When the body can no longer produce enough insulin to overcome the resistance you have type 2 diabetes and likely to be given even more insulin. The result of higher levels of insulin is more weight gain.

Nope, although what you post is a common misunderstanding.

IR means that the cells are resistant to insulin -- it doesn't do it's job and so the body needs to produce more and more. It doesn't result in MORE fat being stored in the cells, however. Just more insulin.

There's no need for insulin to be continually present unless you also just keep eating and eating.

Anyway, bigger point is that typically IR follows obesity, not the reverse. And plenty of obese people aren't IR.

Are you IR, or just assuming? I am not and never was.

As far as if 12 hour fast is valid or not, I'm not sure. Probably everyone hits 12 hours sometimes.

Right -- I'm not saying it's not "valid" but simply not what I'd consider a fast. Eat dinner at 6 (as I occasionally do) and don't eat til 10 the next day or even wait until noon (not uncommon for me on a weekend, although less common than it used to be). That's not a fast in my book. What I consider a fast is nothing for a full day -- like between dinner on Aug 6 and breakfast on Aug 8. IF is not based on full fasts, of course -- for the purpose of IF you do a window or a low cal day (like I said, 5:2 or ADF is what appeals to me).

I mostly run and bike and swim for cardio. I can run fasted without issue, but I have a hard time running and sticking to 500 calories (as on a low day with 5:2) and not struggling. Not sure if that goes away or not, so I've been assuming I'd have to exercise on eating days and take the low days as recovery, but am a bit worried that that might interfere with recovery. I need to just experiment, I suppose.