Question:

If everyone were rich and had access to healthy local organic produce and always ate an ideal diet and exercised in an ideal way, would everybody`s BMI be between 18.5-24.9 throughout their entire life?

Answer:

Unfortunately, the answer to your question is not known. We do not have research data about persons who eat an “ideal” diet with “ideal” physical activity throughout a lifetime. Researchers have examined epidemiological data and have found that countries that tend to have healthier lifestyle habits also have lower rates of obesity (healthier BMIs), but we cannot be certain that the lifestyle habits cause the healthy weights. Genetics is another important factor for the regulation of energy balance and body weight. In fact, genetics may be responsible for a large percentage of the variation in body weight among individuals. So genetics and lifestyle habits together influence BMI.

Researchers also have examined the trends in obesity over the last 3 decades in the United States. They have concluded that the marked increase in obesity during a relatively short time most likely is due to changes in our environment rather than changes in our genetic profiles. There has been an increase in automation and sedentary activities (causing lower energy expenditure) and an increase in high-calorie, readily available foods (causing higher energy intake). With a higher intake of calories and lower energy expenditure, persons (especially those who are genetically susceptible) are at risk for overweight and obesity. Although we cannot change our genetics, we can adopt a healthy diet and regular physical activity to achieve the best state of health possible.

For more information:

Go to the Healthy Weight Center health topic.