Friday, September 18, 2009

Genetics & obesity - we can't blame our parents anymore!

There was a recent article that discussed the genetic link to obesity. Research states you have a 2.5x greater risk of being obese if you have 2 copies of the best known gene for overweight and obesity. Hmm, so if Mom & Dad both give me copies of this gene, I'm doomed to be fat? Or worse yet, "obese"? NO!

A study published in the American Journal of Clinical Nutrition(1) found that obesity can be affected by dietary intake and leisure-time activity. Let me summarize:

  • The study followed over 4800 people from a diet & cancer study for which dietary data and genetic information was available.

  • Results indicated that those subjects who consumed a higher fat and lower carbohydrate diet had a higher body mass index (BMI) compared to those who consumed a lower fat diet.

  • Those with an increased BMI also reported less physical activity.

  • The authors concluded that high-fat diets & low activity may accentuate the susceptibility to obesity by this specific gene variant.

Well...sounds like nothing new. We all knew that high fat intake (not to mention, high sugar) combined with little exercise leads to obesity. However, the key to this study is that you're not destined to be obese simply because you have 2 copies of this gene! Genetics can be changed with lifestyle modification! That is GREAT news (in my opinion, anyway!)

Keep in mind some study limitations:

  • it's a cross-sectional study, which just looks at a subset of people at a given time. This limits the ability to investigate actual cause (seems like a big limitation)!

  • This is also only a "snap-shot" of 1 week of a subjects self-reported food intake, not a view of his whole life

  • Some of the associations made between diet, exercise & obesity may be lessened due to a dietary recall method relying on a subjects ability to accurately report intake and activity.

Bottom line: despite all the limitations of this study, it still provides us with information that you're not destined to a life of obesity predicted by your genes! Make healthy choices most of the time, be active daily and you can positively change your genetic predisposition!


1. Sonestedt E. et al. Fat and carbohydrate intake modify the association between genetic variation in the FTO genotype and obesity.

Tuesday, August 4, 2009

calorie restriction - best way to prolong life & prevent disease?

A recent study completed at the University of WI-Madison found that rhesus monkeys lived longer when calories were restricted by 30% (80% of the calorie restricted monkeys were alive after 20yrs vs. 50% of free eating monkeys). Furthermore, their incidence of cancer and cardiovascular was significantly reduced; and no animal in the calorie restricted group developed diabetes or impaired glucose regulation.

The lead researcher states “we observed that caloric restriction reduced the risk of developing age-related disease by a factor of 3 and increased survival. Our data indicate that adult-onset moderate caloric restriction delays the onset of age-associated pathologies and promotes survival in a primate species” (emphasis mine). Wow, this is great news for rhesus monkeys! The authors go on to discuss the “given parallels” between rhesus monkeys and humans, therefore these beneficial effects of calorie restriction may also occur in humans. Albeit, there may be “parallels” between humans and monkeys, we are still quite different! It is difficult to apply this research to humans and expect the same outcome, let alone compliance!

There is an ongoing study called CALERIE ( which puts normal weight individuals on 25% fewer calories than their baseline requirements (other groups cut calories by as much as 40%). Baseline requirements vary by individual & this may result in a diet of about 1200-1500 calories/day for some people – which is quite low. Keep in mind; you can decrease calories simply by choosing healthier foods and using healthier cooking methods. It’s much more difficult to consume a high calorie diet when you choose whole, unprocessed food!

I don’t feel restricting calories by 25% is necessarily the answer to achieving long-term health. Sure there are studies out that show you can increase longevity & decrease onset of disease but if I’m going to be “on edge” everyday because my calories are restricted, let alone trying to keep up my workout routine…no thank you!

Look at all the failed attempts by many who tried to lose weight by cutting calories (a.k.a. starvation); and when you gain the weight back…I’m sorry to say, it’s not muscle! You can achieve the same results other ways - my suggestion is to avoid (yes, I mean AVOID) processed, refined white flour, white sugar foods, choose lean protein, healthy fats (omega-3), and plenty of colorful vegetables (limit starchy carbs to about 40% of your total intake). And participate in an exercise program that will continually challenge you. If that means hiring a personal trainer, then do it. By making these simple changes you can easily indulge in a treat here and there without losing sight of your goals!

Source: R.J. Colman, R.M. Anderson, S.C. Johnson, E.K. Kastman, K.J. Kosmatka, T.M. Beasley, D.B. Allison, C. Cruzen, H.A. Simmons, J.W. Kemnitz, R. Weindruch. "Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys" Science. 10 July 2009, Volume 325, Pages 201-204