Musings on Metabolism

I recently came across this short article in the New York Times, entitled "Nigeria: Those Born During Biafra Famine Are Susceptible to Obesity, Study Finds", which describes how the children of those who were born to women starving during a country-wide famine have grown up to be more likely to suffer from obesity than those born of women who had enough to eat during their pregnancies. This article got me thinking: did the mother's starvation trigger a metabolic change in the foetus, in other words, was the foetus's metabolism slowing down in order to conserve as much fat (an energy source) as possible in order to survive? I'm not a scientist, but I think this is about as good as hypothesis as any, especially in view of the masses of anecdotal evidence showing how dieting messes with your metabolism and sets you up for a lifetime of starvation in a quest to maintain a lower body weight.

When the body is radically undersupplied with the number of calories it needs to maintain a steady weight, it does not perceive this as simply a "diet". The mind may think it is acting reasonably by controlling calories ingested and burning additional calories through exercise (dieting) while the perfectly designed body--working only on the instinct to survive--fails to distinguish between starvation pure and simple and this "diet".

Since the body only recognizes a state of starvation or a state of non-starvation, what does it do when it notices that it is starving? Simple: it goes into energy conservation mode. It seeks to protect what is most precious to its survival--fat--while using up the "less important" muscle stores. The human body is a master at adapting. Fewer calories in? Let's burn fewer calories since we're under attack and in danger of dying of starvation. That's the metabolism story. I suspect that's also the story of the obese Biafran adults of today.

A perfect example of how metabolism adapts (read: slows down) can be found below in Andrea's story (quoted with permission from Andrea in a response to a post on Debra's Just Maintaining):

It’s decidedly unfun to have regained 25 lbs. (of a 49 lb. weight loss) over the past two years while eating “moderately,” “intuitively,” and “healthfully,” and while exercising 5-6 days a week doing a combination of step aerobics, hi/lo aerobics, and pretty intense strength training, all done to the DVD workouts of the most advanced instructors in the industry (cardio done on all exercise days, strength sessions 3x/week -total exercise time per week 5-6 hours).

I swear I have read AND implemented all the recommendations and I just cannot maintain the weight loss without RESTRICTING my food intake and UNDEREATING. But, if I do that for too long, the “EAT” impulses get very strong and I eventually succumb. I would actually get “EAT NOW” impulses in the middle of the night and couldn’t fall back to sleep until I ate something, which was usually a piece of grilled chicken leftover from dinner or some reduced fat cheese or sliced turkey breast. It was crazy! Trust me, standing in front of an open refrigerator jamming Pollyo part-skim mozarella sticks into your mouth at 3am is really pretty cuckoo. Thankfully those episodes have stopped since I’ve gained weight.

Lest anyone think I had dieted myself to underweight, that wasn’t the case. I’m 5’6″, lost down to 147 lbs. and I’m now at 172 lbs. I don’t eat processed foods of any kind, I don’t eat out in restaurants, I cook all my meals from scratch, I eat a Meditteranean style diet, I eat tons of fresh vegetables and fruits (produce bill is outta control!), I don’t stuff myself, I don’t eat sweets AND I exercise vigorously. It drives me crazy that it’s assumed that I somehow didn’t make the necessary “lifestyle changes” because if I did I wouldn’t have regained.

The biggest myth we are fed (pardon the pun) is that once we have reached the magic number and have made those "lifestyle changes", we will be able to eat "normally". By normally, I mean eating the number of calories that your height, (new, reduced) weight and exercise expenditure should allow you to eat without regaining. Time and time again, people find that this just isn't true. Like Andrea (and Debra and countless others), they must continue to "undereat", stingily meting out a low-calorie diet to their mildly starving bodies for the rest of their lives to maintain the hard-won weight loss. And I'm referring here to people who did not revert (or perhaps never even indulged in) the fast-food lifestyle. Once again, I refer you to Andrea's comments: fresh, unprocessed food, eaten in moderation, coupled with regular, vigorous exercise...leading to weight re-gain unless caloric intake is consciously and constantly restricted.

I have a number of questions: Are some of us innately more prone to easy gain weight, no matter what our eating profile? If you are, shall we say, naturally on the heavy side, will a "clean" eating regimen only somewhat mitigate your overweight state or just slow down your return to being overweight? Is this propensity exacerbated by a lifetime of dieting, in other words, training our bodies to only maintain the new, lower weight in a semi-starved environment? What is dieting doing to our metabolism?

I am always distressed to read about bloggers who have thought they had graduated to "normal" eating, only to find that they were packing on the pounds as soon as they departed from significant caloric restriction. I'm not talking about people who have gone from perfect dieting to out of control binging. Just people like Andrea.