The Framingham Heart Study

One line of evidence comes from people involved in the Framingham Heart Study, which dates back to the 1940s. Back then, very little was known about why people had heart attacks. This landmark study, which continues to this day, sought to answer that question. In 1948, researchers recruited more than fifty-two hundred men and women between the ages of 30 and 62 who were living in the Boston suburb of Framingham, Massachusetts. They recorded their height, weight, family health history, and gave them a physical exam every other year.

Over the years, scientists began collecting more data from the participants, such as measuring their blood pressure and cholesterol levels, and asking them about their eating, exercise, and smoking habits. In 1971, the Offspring Study, which includes the children (and their spouses) of the original group, was launched. And researchers began recruiting the third generation in 2002. Among the most important discoveries from the study was that cigarette smoking and obesity increase the risk of heart disease, and physical activity could lower that risk.

Researchers also found that over about a thirty-year period, the average participant gained about 20 pounds. This typical, slow gain is healthy and normal. The number of calories these participants ate balanced the number of calories they burned within a tiny percent during those years. If you figure that the average person eats about one million calories per year and you calculate the energy cost of those 20 pounds (that is, how many extra calories would a person have to eat each day, on average), it comes out to about 10 additional calories per day. That’s less than The amount of calories in a single jelly bean! The body’s internal control system is very is precise.

Source: George L. Blackburn, M.D., Ph.D., "Break Through Your Set Point: How to Finally Lose the Weight You Want and Keep It Off," 2008