New research shows that women who don't try to eat less more than double their risk of substantial weight gain in middle age. If you're a 40-something woman, whether you're thin or overweight, the odds are that you'll gain weight over time if you don't make an effort to cut back on what you eat.

The finding comes from a study of nearly 200 women with an average age of 40. At the start of the study the women underwent detailed physical exams, and underwent a seven-day analysis of the food they ate.

Three years later, they underwent another round of physical exams and food-intake analysis. The bottom line was no surprise -- they tended to gain weight and body fat as they aged and became less physically active.

However, not all women gained weight. Even if they didn't exercise more, women who made an effort to eat less were 69 percent less likely to gain more than 2.2 pounds and were 2.4 times less likely to gain 6.6 pounds or more.