Why does my weight drop after I eat more?

At the start of the study, the men were losing weight linearly, dropping about 2 lbs per week. However, after some time the weight loss became erratic and unpredictable. No longer was it linear, but rather it occurred in "bursts" with long periods of plateaus. The researchers overseeing the experiment noted that water retention was noticeable in most men and in some cases quite severe.

Half-way through the study the men were allowed a relief dinner to celebrate their progress. One big meal of 2300 kcal was served; roasted chicken, potatoes, gravy and strawberry shortcake. That night everyone got up more often than usual to urinate. The next day they discovered that they had each lost several pounds.

This was not a one-time occurrence. When the experiment was over and the refeeding phase began, the men continued to drop weight at an accelerated rate until calories were increased substantially.

What I want you to take away from this is the following:

* Refeeding can cause rapid weight loss, a whoosh. This seems counter intuitive, but it's a phenomenon observed in the scientific literature and retold by many dieters. My clients experience this, and so do people embarking on diet regimens where planned carb refeeds are integral parts of the plan (for example, The Ultimate Diet 2.0).

* In my experience, the more severe and rigorous the diet, the higher the likelihood of retaining water. In simple terms, higher calorie deficits usually result in more erratic, non-linear weight loss. This is not a proven fact, but rather a hypothesis based on what I have observed throughout the years - and it has some backing if we look at the weight loss curve observed in starvation and studies like The Minnesota Experiment.

* The hypothesis has credibility if we look at the hormonal response to starvation diets. "Starvation diets" in this context simply mean any diet approach that results in a very high weekly caloric deficit created through diet and/or exercise. This is perceived as a significant stress to the body, to which it responds with chronically raised levels of cortisol. Some cortisol is great, but too much of it is very bad; and studies suggest that cortisol increases in a dose-dependent manner related to the calorie deficit. Prolonged elevations of cortisol can lead to massive water retention. If you've ever been treated with hydrocortisone, a pharmaceutical form of cortisol, you know what I mean.

http://www.leangains.com/2010/01/how-to-deal-with-water-retention-part.html

This article doesn't discuss the exact biological mechanism but the important point is

At the start of the study, the men were losing weight linearly, dropping about 2 lbs per week. However, after some time the weight loss became erratic and unpredictable. No longer was it linear, but rather it occurred in "bursts" with long periods of plateaus. The researchers overseeing the experiment noted that water retention was noticeable in most men and in some cases quite severe.

Half-way through the study the men were allowed a relief dinner to celebrate their progress. One big meal of 2300 kcal was served; roasted chicken, potatoes, gravy and strawberry shortcake. That night everyone got up more often than usual to urinate. The next day they discovered that they had each lost several pounds.

This was not a one-time occurrence. When the experiment was over and the refeeding phase began, the men continued to drop weight at an accelerated rate until calories were increased substantially.

What I want you to take away from this is the following:

* Refeeding can cause rapid weight loss, a whoosh. This seems counter intuitive, but it's a phenomenon observed in the scientific literature and retold by many dieters. My clients experience this, and so do people embarking on diet regimens where planned carb refeeds are integral parts of the plan (for example, The Ultimate Diet 2.0).

* In my experience, the more severe and rigorous the diet, the higher the likelihood of retaining water. In simple terms, higher calorie deficits usually result in more erratic, non-linear weight loss. This is not a proven fact, but rather a hypothesis based on what I have observed throughout the years - and it has some backing if we look at the weight loss curve observed in starvation and studies like The Minnesota Experiment.

* The hypothesis has credibility if we look at the hormonal response to starvation diets. "Starvation diets" in this context simply mean any diet approach that results in a very high weekly caloric deficit created through diet and/or exercise. This is perceived as a significant stress to the body, to which it responds with chronically raised levels of cortisol. Some cortisol is great, but too much of it is very bad; and studies suggest that cortisol increases in a dose-dependent manner related to the calorie deficit. Prolonged elevations of cortisol can lead to massive water retention. If you've ever been treated with hydrocortisone, a pharmaceutical form of cortisol, you know what I mean.

Basically, the answer seems to be water retention. I read somewhere that as glycogenolysis increases during calorie restriction, water weight also increases. Because more water will be required during increased glycogen usage. A rapid decrease in glycogenolysis would lead to a rapid decrease in water. I still cannot find a source for that so I cannot back it up with anything.

You mentioned that on my status a few days ago, and it was interesting. I was hoping someone could come up with something a bit authoritative. It's a reasonable explanation, certainly, and I suppose I'll have to run with it. Thanks for the quote.

Ya I plan on having quite a high calorie day today. I will be having BBQ and lots of easter chocolate.

I'll just consider it an experiment for, you know....science!

By eat just 500 calories a day you are putting your body into starvation mode. Women need at least 1200 calorie and men 1500 calorie just for the body to function.