Obesity And Chronic Disease- Is It Genes Or Lifestyle?

While there is a clear correlation between physical inactivity and bad dietary habits to most chronic diseases in the world today, many offer up genetics and not lifestyle as the major reason for our higher incidences of obesity and the metabolic syndrome that tends to accompany it. Almost 60% of the adult American population is either overweight or obese [1, 2,3] and it is becoming increasingly common to hear genes blamed as the root of our current health crisis. In many ways this rather defeatist attitude would lead one to believe that the leading causes of death in Western society (coronary heart disease, hypertension, stroke Type 2 diabetes and cancer) are not preventable and that to succumb to the ravages of these diseases is simply a normal part of the aging process. Taken as a whole, these diseases combine to account for almost 70% of all of the deaths here in the United States [4], and few realize that that these health problems have been for the most part non-existent in many underdeveloped countries for decades, but rise as Western diet and lifestyles become more popular in those countries. [5]

Do Other Cultures Have The Same Problems With Obesity & Disease That  We Do?

To fully understand the impact that our genes have on our health it is useful to observe how other cultures fare when Western diet and relatively sedentary habits are not a factor in daily life.  Studies on the Tarahumara Indians of Northern Mexico, (best known for their running ability), the Pina Indians of Southern Arizona and the Machiguenga Indians of Peru give us interesting insight as to just how much Western lifestyle seems to adversely affect our health. The Pina Indians living on the Indian reservation in Arizona have one of the highest incidences of diabetes known, with approximately 50% of them being Type 2 diabetic. However a group of Pina Indians with the same genetic background as their reservation-living counterparts following a more physical indigenous life in Mexico eating the traditional diet of natural foods have an incidence of Type 2 diabetes of only 10%.[6,7] Similarly when the Tarahumara Indians consume a mostly Western diet they rapidly experience a rise in their blood lipids when compared to their native counterparts. [8]. The Machiguenga Indians, due to the physical requirements for survival without the luxuries of supermarkets and packaged foods expend one third more calories than the average American [9] and chronic diseases as we know them are simply non-existent in modern hunter gatherer societies, highlighting the role of lifestyle in the development of obesity and metabolic disease. [10]

Genes Cannot Be The Only Answer To Obesity & Metabolic Disease

In a paper published in the Journal of Applied Physiology by Frank Booth et al. called, Waging war on modern chronic diseases: primary prevention through exercise biology, researchers note that

“100% of the increase in the prevalence of Type 2 diabetes and obesity in the United States during the latter half of the 20th century must be attributed to a changing environment interacting with genes, because 0% of the human genome has changed during this time period.” [11]

In essence, we have not changed. Our genes have not changed, but our way of life and the foods we eat have changed and this more than anything else explains the problems faced by in Western societies. We all inherit the same genome that makes us designed for daily physical activity and a high fiber diet[12] thus sedentary life, processed foods combined with other factors such as smoking alcohol consumption, stress and hazardous elements in our environment inevitably bring about the onset and progression of chronic disease. [10] Most of these factors are easily modified and therefore are realistically preventable through proper diet, exercise and a lifestyle of moderation or abstinence from smoking and excess alcohol consumption. Within the framework of our own society it has been observed that Seventh-Day Adventists have higher life expectancies than other Caucasian groups in the United States thanks in part to choices regarding their diet, patterns of regular exercise and avoidance of cigarettes and alcohol. Research funded by the U.S. National Institutes of Health has shown that the average Seven Day Adventist in California lives 4 to 10 years longer than the average Californian. Similarly Mormon studies show that they have a low standardized mortality rate compared to the general U.S. population attributed to their close to the earth lifestyle.[13]

Lifestyle & Environment Not Genes Create Our Health Problems- Not Genes

What does this mean? It means that for the most part genes don’t cause metabolic disease. In some individuals genetic factors may predispose them, but environmental and lifestyle factors are what determines whether disease manifests itself or not [10]. It also means that we are indeed the masters of our own destiny, captains of our own ships and that an individual’s choice to incorporate exercise into their daily life, manage stress and avoid modern processed foods makes far more of a difference in our susceptibility to the cocktail of chronic disease than the genes that we are born with. Make your choice today.

References:
1. Flegal KM, Carroll MD, Kuczmarski RJ, and Johnson CL. Overweight and obesity in the United States: prevalence and trends, 1960–1994. Int J Obes Relat Metab Disord
2. Mokdad AH, Bowman BA, Ford ES, Vinicor F, Marks JS, and Koplan JP. The continuing epidemics of obesity and diabetes in the United States. JAMA 286: 1195–1200, 2001.
3. Mokdad AH, Ford ES, Bowman BA, Dietz WH, Vinicor F, Bales VS, and Marks JS. Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. JAMA
4. Arias E, Anderson RN, Kung HC, Murphy SL, and Kochanek KD. Deaths: final data for 2001. Natl Vital Stat Rep
5. Diet, nutrition, and the prevention of chronic diseases. World Health Organ Tech Rep Ser
6. Bennett PH. Type 2 diabetes among the Pima Indians of Arizona: an epidemic attributable to environmental change? Nutr Rev 57: S51–S54, 1999
7. 1Valencia ME, Bennett PH, Ravussin E, Esparza J, Fox C, and Schulz LO. The Pima Indians in Sonora, Mexico. Nutr Rev
8.  McMurry MP, Cerqueira MT, Connor SL, and Connor WE. Changes in lipid and lipoprotein levels and body weight in Tarahumara Indians after consumption of an affluent diet [see comments]. N Engl J Med 325: 1704–1708, 1991
9. Montgomery E. Towards representative energy data: the Machiguenga study. Fed Proc
10. Roberts CK, Barnard RJ.  Effects of exercise and diet on chronic disease. J Appl Physiol
11. Booth FW, Gordon SE, Carlson CJ, and Hamilton MT. Waging war on modern chronic diseases: primary prevention through exercise biology. J Appl Physiol
12. Eaton SB and Konner M. Paleolithic nutrition. A consideration of its nature and current implications. N Engl J Med
13. Enstrom JE. Health practices and cancer mortality among active California Mormons. J Natl Cancer Inst