Fat And The Year You Were Born

By Dr. E. Kirsten Peters

New Year’s resolutions are being put to the harshest of tests. Gone are the days of early January when all things seemed so easily possible. Now we are in the tougher phase of the year when the will to establish new patterns is being sorely tested by the tug of old habits.

One of the most popular resolutions Americans make, year after year, is to lose weight. Earlier studies have shown a correlation between being overweight and having a specific variant of the gene called FTO. Now a study reported in PNAS Early Edition makes the case that the year you were born plays a crucial role in fat accumulation — whether you have the variant of the FTO gene or not. In short, there is no correlation between FTO and obesity in people born longer ago, but there is a correlation for people born more recently.

This work comes out of a very long-running study called the Framingham Heart Study that follows individuals over decades. The lead author of the PNAS report is Dr. James Niels Rosenquist of the Massachusetts General Hospital.

Rosenquist told ScienceDaily that “(our) results…suggest that this and perhaps other correlations between gene variants and physical traits may vary significantly depending on when individuals were born, even for those born into the same families.”

The new work comes out of long-term follow-ups with the children of participants in the original Framingham Heart Study. Called the Framingham Offspring study, the later research consisted of following people from 1971 — when the people ranged from 27 to 63 years old — through 2008.

Looking at body mass index (BMI), the medical researchers found that only for people born in later years was there a correlation between the FTO gene variant and obesity.

What’s so magical about the year of your birth and the struggle to win the battle of the bulge? The study couldn’t nail down specific answers, but it seems likely there are a couple of factors. For instance, more and more of us have sedentary jobs. But beyond that, there has been an increasing reliance on processed foods, with less cooking from scratch — a fact that may shape eating habits particularly for the young. Eating processed foods tends to correspond to consuming more calories, a double whammy for those of us who don’t get exercise at work.

“The fact that [the] effect can be seen even among siblings born during different years implies that global environmental factors such as trends in food products and workplace activity…may impact genetic traits,” Rosenquist said. “Our results underscore the importance of interpreting any genetic studies with a grain of salt.”

My take away from the report is that both diet and exercise remain the keys for taking off weight. Good luck to all of us as we try to reform habits early in this New Year.

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.