Will Restricting Food Promote Obesity?Thursday, March 18, 2010
Last week, an article in the New York Times with the title “The Obesity-Hunger Paradox“, addressed the issue of food insecurity – or how, not knowing when or where your next meal will come from, can make you overeat – thus promoting obesity.
Interestingly, this month’s issue of OBESITY uses an animal model to illustrate a similar point.
In this study by Xingshenk Li and colleagues from the University of Alabama, one set of mice was first allowed free access to food for six weeks and was then mildly calorie restricted (5%) over three more weeks during which the animals were provided access to food only once a day. In a second experiment mice were either mildly calorie restricted or had free access to food.
Interestingly, one of the big changes in feeding behaviours with calorie restriction was overeating, where the mice ate almost four times the amount of food in a two hour period, than when they had free access to food.
Importantly, despite the overall calorie restriction, the researchers found no change in body weights – rather, the calorie-restricted mice appeared to become fatter, exchanging fat for lean tissue. They also showed a significant reduction in energy expenditure.
The researchers interpret their evidence as supporting the notion that the gorging behaviour in response to food “uncertainity” alters energy partitioning resulting in more effective triglyceride production and fat storage. This altered metabolism may in part be due to the hormonal changes resulting from the “stress” of calorie restriction.
Clearly, these findings should be of interest to those of us who wonder about the long-term effects of caloric restriction, meal skipping, and binge eating.
The study may also explain why chronic (especially intermittent) dieting can be counterproductive and in some individuals paradoxically increase fat stores.
Certainly the study should remind us that any restriction of food intake (whether voluntary or involuntary) can profoundly change our “feeding” behaviour and change the way our bodies handle calories.
The next time you wonder why you or your patients are not losing weight despite restricting calories, remember that there is apparently no end to the tricks our body will come up with to protect its weight.
Thursday, March 18, 2010
As a counter trick to this tendency (I called it “panic eating” before I knew of any studies) I have found it helpful to plan meals the day before.
With a plan in place, there is not the “oh no, I’m going to get really hungry” panic feeling that derails many diets. Being mildly hungry becomes something to be expected before each scheduled meal or snack, which is quite ordinary.
Mice are unlikely to jot down their upcoming meals in their day planners. They are at the mercy of the experimenters.
We, however, can plan ahead. Now that we know scarcity and unpredictability provokes overeating and over fat storage, we can plan a schedule and a diet that trains the body to expect food at regular predictable times throughout the day. Calorie restriction leading to fat loss might be possible psychologically and metabolically in this context.
Are there any studies on overweight mice which parallel overweight people trying to lose excess fat?
For example: feed the overweight mice 5 times a day, on a predictable schedule, giving them at each feeding slightly fewer calories than are needed to maintain their overweight.
I wonder how that would affect their metabolism, fat storage, lean tissue, weight, etc.
Thursday, March 18, 2010
Anon, I agree. I think you hit on a key issue: planning meals and feeding regularly five times a day with a slight deficit (which is what I’m doing most days) can avoid the scarcity issue and help with weight loss. I’d love to see that study in rats. I have seen it in humans, and it works (to promote lean tissue and reduce body fat and weight over time) from what I can tell if you stick with it as a life plan… not a short diet.
Monday, March 22, 2010
I’m reading a book by Ellyn Satter called “Your Child’s Weight: Helping without Harming” and it is based on this principle… that restricting food from a fat child (or even pushing food on a thin child) can lead to disordered eating patterns with regards to control. She recommends a division of responsibility, where the parent chooses the what, when, and where a child eats, while the child decides how much and whether. The idea is that a child who is able to trust their food source, as well as trust their own ability to self-regulate feeding, will have a healthier relationship with food in the long run. It really is an eye opening book and I would recommend it to anyone.
Thursday, March 25, 2010
Repectfully, Dr. Sharma, I would submit that your last line of this post could be reworked a bit to be more compassionate toward people who are trying to balance weight, health, hunger, satiety, food security and sanity.
Instead of saying “The next time you wonder why you or your patients are not losing weight despite restricting calories, remember that there is apparently no end to the tricks our body will come up with to protect its weight.”
You might say “The next time you wonder why you or your patients are not losing weight despite restricting calories…” consider that maybe a different approach is needed. Our bodies are designed to preserve weight, to maintain homeostasis, to protect us against famine and to insure we have sufficient fat stores to reproduce and raise vulnerable human children unable to provide for themselves for many years. Focusing on getting movement that is fun or meaninful to us (could be dancing, biking, gardening, volunteering) and eating food with the greatest nutritional and pleasure payoff for the least calories (such as local fresh foods rather than processed foods designed to be shelf-stable for many seasons) can help us work with, rather than against, our bodies. Moving away from a focus on weight to a focus on overall well-being is one way of “tricking” our bodies into doing what we want (utilizing some of our stored energy to meet our goals and needs) rather than burning fat for it’s own sake (even for the sake of “health”).
I also completely agree with Shannon. I think a merging of your vantage point and Ellyn Satter’s could be extremely powerful.