For this Thursdays Science & Nutrition Nuggets I share with you research reviews regarding evidence-based strategies to treat obesity, how exercise may benefit weight loss beyond calories burned, and whether we should all run scared from fish oil as a cause for increased prostate-cancer risk.
A Review of Evidence-Based Strategies
to Treat Obesity in Adults
The above is the title of some research published in “Nutrition in Clinical Practice / Vol. 26, No. 5, October 2011.”
“Obesity is the result of a chronic surplus in energy intake relative to expenditure. While the specific causes remain unclear, obesity is thought to arise from a dynamic interaction between an organism’s biology, behavior, and the increasingly obesogenic environment.”
One trend I’ve been observing over the past couple of years is more and more research is finally moving beyond the ridiculous notion that weight loss and weight maintenance are simply “calories-in calories-out” events. I’ve been yelling this from every mountain top for about 10 years and it’s nice to see the research finally talking more and more about the complexity and interaction of the “organism” and their obesogenic environment.
A few other key take-home points from this piece of research include:
- Doctors have a primary responsibility to give attention, information and resources to their overweight patients.
- The authors recommend regular measurements of weight, body fat and waist circumference. I agree. We can’t manage what we don’t measure.
- Behavior-based weight loss (what we focus on at LL University) can be effective for promoting adherence to a weight-loss program.
- I also agree with the authors who say “…ongoing support is desirable to counter recidivism.” Absolutely true!
- The authors take a very anti-supplement stance saying there are NO effective supplements for weight control. The authors are not specifically talking about your multi-vitamin/mineral, protein powders, and meal-replacement powders etc. They are speaking more about supplements specifically marketed as fat-loss and/or thermogenic weight-loss supplements.
- Drugs approved by the FDA and only available by prescription may be effective and fall into two classes: 1). dietary fat inhibitors and 2). anorexins (i.e., appetite suppressants). “Both types are more effective when combined with additional weight loss practices such as calorie restriction, exercise, and behavioral modification.” Once again, NOTHING works unless you bring in behavior modification and a real lifestyle-based system.
- For very obese persons who have failed with other approaches, a surgical procedure such as the RYGB or AGB can promote significant weight loss and improve obesity comorbidities, although the risks of these procedures must be carefully considered.
- Once again the researchers are supportive of other published work that says even a modest weight loss of 5%-10% has significant health benefits. They also go on to state that as modest as this may be it’s difficult to maintain so “Ongoing support for behavior change is essential and can best be delivered by a multidisciplinary team, including the patient’s physician and experts in nutrition, exercise, and behavioral therapy.”
The “Chicken Or The Egg” of Physical Activity
And Weight Loss
What do I mean by “chicken or the egg?” Most people involved in the business or personal-achievement of weight loss think of exercise as a way to burn additional calories above their resting-metabolic rate (RMR). But I’ve long believed and taught that while exercise may only “count” for 20% to 30% of the overall net effect weight-fighters will realize, with 70% to 80% of the weight-loss secret being nutrition, there’s a factor less-often discussed but no less important than the caloric effect exercise provides.
What mental, emotional and “neurocognitive” benefits does exercise bring to the table beyond the caloric effect? Not in the mood to eat well? Can exercise improve the “mood?” Just don’t have enough energy to get through your day? Does exercise, especially first thing in the morning, boost energy somewhat throughout the day? Despite best intentions to eat “clean” and “healthy” as the day wears on one or two poor choices are made and yet another day is blown. Might exercise improve the neurotransmitter profile in the brain so that feel-good chemicals are enhanced with increased consciousness regarding food decisions? Is it possible this increased consciousness coupled with a concerted effort NOT to undo the good done by exercise with poor food choices could result in a more-consistent weight-loss pattern?
This is what I mean by “chicken or the egg.” Nutrition IS king for weight loss. It is. It is. It is. But are better nutrition decisions just an exercise session away? For some the answer is absolutely “Yes!” I see it all the time with my clients. So while nutrition IS king if exercise can be thought of as another pathway to better nutrition choices then we really do have a chicken and egg scenario. Which is really first?
The authors of a study (Obesity reviews (2011) 12, 800–812) I reviewed looked at some of these very issues and here are some key take-home points:
- “… physical activity may indirectly influence health behaviours like smoking, substance abuse, risk taking, over-eating and stress management (obesity reviews (2011) 12, 800–812”
- “Adapted cognitive processes and resultant behaviour patterns underlie these so-called ‘goal-oriented’ actions, such as resisting high-calorie foods and increasing physical activity to align with a weight-loss goal.”
- “… higher cardiorespiratory fitness levels were associated with lower percentage of energy from fat, higher dietary fibre intake, reduced cholesterol intake and closer adherence to dietary recommendations.”
- “… men and women who reported increases in their activity levels from age 33 to 42 also reported improvement in the overall quality of their diet.”
- “Different lines of research suggest a positive influence of physical activity on the self-regulation of eating behaviour.”
- “Physical activity can improve executive functions, self-efficacy and mood”
This research paper was interesting and if you’ll notice not one quoted bullet above talks about the calories burned from exercise. But wouldn’t you agree that all of the above can have a dramatic impact on the food-choices made and ultimate scale behavior? I would.
Fish Oil CAUSES Increase Prostate Cancer! Well, not exactly
In response to a brief reminder I wrote on this blog to take omega-3 fish oil or consume it from fatty fish like salmon one person commented (which I really do appreciate) that he had heard that fish-oil supplements could cause an increase in prostate cancer. The commenter wasn’t sure of the source of the study but a respected doctor at a hospital he works at had mentioned it recently.
Well I had actually remembered reading the abstract a while back but never got the full study – until now. The study my commenter was referring to was out of the Am J Epidemiol. 2011;173(12):1429–1439.
“EPA and DHA, found in fatty fish and in fish oil supplements, are hypothesized to reduce cancer risk through their antiinflammatory and immunomodulatory properties.” In another place in their research report they state “There were no associations of low-grade prostate cancer with any fatty acid measure.” So far so good – all makes sense.
And then they got a surprise.
“Indeed, our findings are disconcerting as they suggest that n-3 fatty acids, considered beneficial for coronary artery disease prevention, may increase high-grade prostate cancer risk, whereas trans-fatty acids, considered harmful, may reduce high-grade prostate cancer risk.”
The authors duly note limitations of their study and possible confounding variables for their unexpected results. I’ve also yet to meet a real science-minded individual who looks at one study and says “Ureka! This is the end-all be-all definitive guide to this subject!” However, this study was large and apparently very well done.
What does it really mean? Well it’d be improper to say that omega-3 fats increase prostate-cancer risk. While the surprising results are not good the increased risk was specifically for high-grade prostate cancer, not low-grade prostate cancer.
I think the authors conclude with the best guidance.
“These findings illustrate the complexity of research on nutrition and chronic disease risk, in which the effects of nutrients may differ across multiple diseases. A comprehensive understanding of the effects of nutrients on a broad range of diseases will be necessary before making recommendations for dietary changes or use of individual dietary supplements for disease prevention.”