Eating Fatty Foods and Excess Calories Doesn't Cause Weight Gain, Multiple Independent Studies Show

Fatty foods -- such as double bacon cheeseburgers, butter, and pork chops -- are often implicated as a prime cause of obesity. But, contrary to what we've all been taught, overeating calories and eating lots of fat does not appear to lead to weight gain.

That's a surprising contention. But this counterintuitive view about fatty foods has good support:

1. Here's a report published in Science magazine on January 8, 1999: 'Role of non exercise activity thermogenesis in resistance to fat gain in humans.'[1]

From the abstract:

"Humans show considerable inter-individual variation and susceptibility to weight gain in response to overeating. The physiological basis of this variation was investigated by measuring changes in energy storage and expenditure in 16 non-obese volunteers who were fed 1,000 kilocalories per day in excess of weight maintenance requirements for eight weeks. Two thirds of the increases in total daily energy expenditure was due to increased non exercise activity thermogenesis (NEAT) which is associated with fidgeting, maintenance of posture, and other physical activities of life. Changes in NEAT accounted for the tenfold difference in fat storage that occurred and directly predicted resistance of fat gain with overfeeding... these results suggest that as humans overeat, activation of NEAT dissipates excess energy to preserve leanness." (bold added)

In this study, the amount of calories people took in from fatty foods was intentionally elevated. But these people didn't get fatter; instead, their metabolisms compensated to keep them at a steady weight. This is NOT what we would expect if the Caloric Balance Hypothesis were true. But it IS what we would expect if the Lipophilia Hypothesis were true.

2. Read this article for more evidence that overeating fatty foods does not lead to fat gain: 'Autonomic nervous system activity in weight gain and weight loss.'[2]

From the abstract:

"Studies in both animals and humans indicate that the autonomic nervous system (ANS) responds to changes in systemic energy balance. In the present study, ANS response to weight change was examined... these findings support the hypothesis that the ANS acts to oppose weight change." (bold added)

This paper seems to contradict the Caloric Balance prediction that conscious manipulation of calories controls our weight. But it supports the Lipophilia Hypothesis, which tells that unconscious physiological factors control our weight.

3. Here's another interesting article about the effects of eating fatty foods: 'Resistance to weight gain during overfeeding: A NEAT explanation.'[3]

From the abstract:

"Individuals vary in susceptibility to weight gain and response to overfeeding; however, the reason for such variation has never been clear." (bold added)

4. And check out this essay from the Journal of Clinical Endocrinology and Metabolism: 'Adiposity signaling and biological defense against weight gain: Absence of protection or central hormone resistance?'[4]

From the abstract:

"An abundant and compelling literature supports the existence of a homeostatic system that dynamically adjusts energy intake and energy expenditure to promote the stability of body fat mass. In the context of the system, the ease with which many individuals gain weight is difficult to explain." (bold added)

The authors then go on to describe a 'central resistance model.' According to this model:

"Under normal circumstances, the energy homeostasis system provides an effective defense against weight gain as well as weight loss and that common forms of obesity involve genetic or acquired defects (or interactions between them) that impair the function of this system." (bold added)

Doesn't this fit in nicely with the predictions of Lipophilia? In fact, the authors even admit that an 'abundant and compelling literature' supports the idea that homeostasis controls fat metabolism. If that's true, it alone refutes the Caloric Balance theory. After all, how can homeostasis control our fat if calories from fatty foods are supposed to?

5. 'How we've come to believe that overeating causes obesity.'[5]

This article from the junkfoodscience blog is biased towards the low carb diet perspective, but it does a good job of summing up the case against the idea that fatty foods and overeating cause weight gain. Here is a good quote form the article:

"Scientists at Rockefeller University ... went on to learn that the body has an incredibly complex and sophisticated system to regulate its fat stores. And when those fat levels deviate... compensatory mechanisms kick in to return the body to its normal state without us having a lot of say about the matter."

6. And, of course, for a full blow by blow account of why overeating fatty foods or excess calories doesn't lead to weight gain, there is no better source than Good Calories Bad Calories. In particular, check out chapter 16 (pages 272 to 291). Taubes describes a study conducted at the University of Vermont in the 1960s, in which state prisoners were put on a regimen of 'forced gluttony.' At first, they ate 4,000 calories a day, then 5,000, and finally 10,000. Some subjects fattened more than others. But when the experiment ended, "all the subjects 'lost weight readily... and with the same alacrity... as that with which obese patients typically return to their usual weights after semi starvation diets."[6]

Taubes also lists several other studies that demonstrate the same idea; namely, that when you force fatty foods and excess calories into peoples' stomachs (and into animals' stomachs), you may be able to artificially cause some weight gain at first. But inevitably metabolism will compensate. And usually, when the forced gluttony ends, subjects return to their previous weights.

Now, obviously, proponents of the idea that "calories count" can nitpick the results of this or that study. But if even one solid experiment shows that overfeeding fatty foods does NOT lead to weight gain, then the Caloric Balance Hypothesis cannot hold. Because that hypothesis explicitly states that when we overeat, we will gain weight. If we overeat and don't gain weight, then that means the hypothesis is almost certainly wrong.

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1. James A. Levine, Norman L. Eberhardt, Michael D. Jensen Role of nonexercise activity thermogenesis in resistance to fat gain in humans Science 8 January 1999: Vol. 283. no. 5399, pp. 212 - 214. DOI: 10.1126/science.283.5399.212.

2. L. J. Arone, R. Mackintosh, M. Rosenbaum, R. L. Leibel and J. Hirsch Autonomic nervous system activity in weight gain and weight loss AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 1 222-R225, Copyright © 1995 by American Physiological Society.

3. Theodore B. Vanltallie M.D. Resistance To Weight Gain During Overfeeding: A Neat Explanation Nutrition Reviews Volume 59 Issue 2, Pages 48 - 51; Published Online: 27 Apr 2009.

4.Michael W. Schwartz and Kevin D. Niswender Adiposity Signaling and Biological Defense Against Weight Gain: Absence of Protection or Central Hormone Resistance? The Journal of Clinical Endocrinology & Metabolism Vol. 89, No. 12 5889-5897 Copyright © 2004 by The Endocrine Society.

5. Sandy Szwarc How we've come to believe that overeating causes obesity Junkfood Science Blog (2/7/2008).

6. Taubes, Gary. "Good Calories, Bad Calories." p 273. New York: Knopf (2007).

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