Overfeeding Obesity

OVERFEEDING OBESITY PRONE AND OBESITY RESISTANT INDIVIDUALS

A few years ago, a small experiment comparing self described (easy) weight gainers with non-gainers gainers came across my desk. I meant to write about it but it somehow never did. Recently, while going through some notes for a lecture, I stumbled on it again.

THE STUDY
Fourteen obesity-prone (OP) and twenty obesity-resistant (OR) subjects were studied for three weeks. In the first week, dietary intakes were established by questionnaires and activity levels were measured with pedometers.

On week two, the subjects either overfed by 40% for 3 days or were fed exactly 100% of their established normal levels for 3 days. Then, for the next 3 days the subjects were allowed to free feed (meaning they were not given controlled portions.) During the 3rd week the subjects received the opposite treatment. Pedometers were used throughout both weeks of the study.

RESULTS
The OP subjects showed no change in activity levels between the week of 3 overfeeding days + 3 free feeding days and the week of 3 eucaloric days + 3 free feeding days.

The OR subjects took an extra 1000 steps per day during the week of 3 overfeeding days + 3 free feeding days compared to their week of 3 eucaloric days + 3 free feeding days.

Then researchers then focused on the 3 overfeeding days only and discovered that the fourteen OP subjects averaged ~ 775 fewer steps per day when they were overfed.

COMMENT
In this study, the OR group took 1000 extra steps a day during the 6 day period that began with the 3 overfeeding days while the OP subjects took ~ 775 fewer steps during the 3 days they were overfed. This calculates to 6000 more steps for the OR group vs. 2300 fewer steps for the OP group. This does NOT mean all OP and OR people will react the same way when they overeat because a single 34 person study is not large enough to establish anything by itself. And, when I was researching to support this comment I stumbled upon a new paper that repeated the protocol with a few more subjects and improved activity measurements. This time, they did not see an activity increase when OR people were overfed but did record an activity reduction when OP individuals overate.

REFERENCES:
1. Sharp, T.A., Horton, T.J., Kealey, E., et al. Effects of Short-Term Overfeeding on Physical
Activity in Obesity-Prone and Obesity-Resistant Adults. Med. Sci. Sports Exerc. 2007; 39(5):
S385, A-2157.
2. Schmidt SL, Harmon KA, Sharp TA, Kealey EH, Bessesen DH. The Effects of Overfeeding on
Spontaneous Physical Activity in Obesity Prone and Obesity Resistant Humans. Obesity. 2012
Apr 23 [Epub ahead of print]. Accessed Aug 12, 2012.

G. Douglas Andersen, D.C., C.C.N.
GDA/lah

D: 08/12/12
T: 08/13/12
081212L-OVERFEEDING ARTICLE
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