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These people were significantly overweight, from almost obese to morbidly obese(by BMI). From such a starting condition initial weight loss can be extremely rap

These people were significantly overweight, from almost obese to morbidly obese(by BMI). From such a starting condition initial weight loss can be extremely rapid, yet after 12 weeks they lost only .94 kg?

arcticbull 6y ago
This is a common source of misunderstanding, so I think it's worth clearing up: Rapid initial weight-loss is usually just a loss of glycogen, the front-line starch form of energy storage in your body. For every gram of glycogen you clear out, 2-3 grams of water goes with it. As soon as you eat anything, all the water comes back instantly. That may be weight loss, but it's definitely not fat loss. The metabolic pyramid roughly goes Alcohol > Sugar > Glycogen > Fat >>> Protein. Useful protein is extremely strongly conserved by your body, especially when fasting. Makes sense right, without your muscles, you wouldn't be able to hunt down and kill your next meal. Fat loss when totally fasted happens basically at a rate of your BMR, which goes up a bit when fasted. This is due to an increase in noradrenalin in the fasted state. Your BMR is roughly proportional to your body weight. A pound of fat contains 3500 calories. Your BMR is roughly ~2000 kcal per day for an average human, plus a bit more when fasted. This means when totally fasted you will lose roughly 2/3 of a pound of fat per day. That rate remains pretty consistent throughout your weight loss regimen. Over 12 weeks, they lost 2 pounds, or 7000kcal. That's a daily caloric deficit of 100kcal. Sounds like they weren't really on much of a diet.
- dgacmu 6y ago
  Which still leaves the GPs question - the subjects averaged a 90 calorie per day deficit. (.94 x 2.2 x 3500 % (12*7)). That's fairly slow weight loss.
  - arcticbull 6y ago
    Indeed.
- JohnCohorn 6y ago
  I’m very familiar with this having recently lost exactly 2lbs per week for many weeks to hit a 35lb total. At least in my experience it really is much easier to lose weight initially. Not sure if there are studies on this or just anecdotes. When I was borderline obese, losing weight was simply a matter of being vaguely mindful about “eating better”. After I lost a decent amount that way losing more took deliberate effort and tracking calories. The people in the study didn’t even lose the weight you would expect from the effect of losing glycogen and water retention.
  - arcticbull 6y ago
    Congratulations! That's an amazing result. I suspect 16:8 with ad libitum eating is not going to trigger a reduction in glycogen, certainly not with 100kcal per day deficit. This feels more like a super light weight caloric restriction diet.

arcticbull 6y ago

This is a common source of misunderstanding, so I think it's worth clearing up: Rapid initial weight-loss is usually just a loss of glycogen, the front-line starch form of energy storage in your body. For every gram of glycogen you clear out, 2-3 grams of water goes with it. As soon as you eat anything, all the water comes back instantly. That may be weight loss, but it's definitely not fat loss. The metabolic pyramid roughly goes Alcohol > Sugar > Glycogen > Fat >>> Protein. Useful protein is extremely strongly conserved by your body, especially when fasting. Makes sense right, without your muscles, you wouldn't be able to hunt down and kill your next meal. Fat loss when totally fasted happens basically at a rate of your BMR, which goes up a bit when fasted. This is due to an increase in noradrenalin in the fasted state. Your BMR is roughly proportional to your body weight. A pound of fat contains 3500 calories. Your BMR is roughly ~2000 kcal per day for an average human, plus a bit more when fasted. This means when totally fasted you will lose roughly 2/3 of a pound of fat per day. That rate remains pretty consistent throughout your weight loss regimen. Over 12 weeks, they lost 2 pounds, or 7000kcal. That's a daily caloric deficit of 100kcal. Sounds like they weren't really on much of a diet.

dgacmu 6y ago
Which still leaves the GPs question - the subjects averaged a 90 calorie per day deficit. (.94 x 2.2 x 3500 % (12*7)). That's fairly slow weight loss.
- arcticbull 6y ago
  Indeed.
JohnCohorn 6y ago
I’m very familiar with this having recently lost exactly 2lbs per week for many weeks to hit a 35lb total. At least in my experience it really is much easier to lose weight initially. Not sure if there are studies on this or just anecdotes. When I was borderline obese, losing weight was simply a matter of being vaguely mindful about “eating better”. After I lost a decent amount that way losing more took deliberate effort and tracking calories. The people in the study didn’t even lose the weight you would expect from the effect of losing glycogen and water retention.
- arcticbull 6y ago
  Congratulations! That's an amazing result. I suspect 16:8 with ad libitum eating is not going to trigger a reduction in glycogen, certainly not with 100kcal per day deficit. This feels more like a super light weight caloric restriction diet.