<p>Such an interesting discussion! OP, I have had just the same issue with a D, and struggled for the words, the approach. I think there are medical issues, to an extent, and she is not willing to explore them. But she does exercise, and is from a family that is active and eats their vegetables, if less than on top of portion control. I feel she’s got some good habits for the future. </p>
<p>But I’ve had my own little experiment that has evolved unintentionally over the college years. Twin A is in a Midwest school, has gained weight, despite being a competitive athlete for part of the year. Twin B is on the west coast, plays a recreational sport, and has taken up running, and worked on weight loss Freshman year, so much lighter now than when she entered college. </p>
<p>The college environment in twin As Midwest town seems to be a very hard one for health, cold, little to do but study and drink, and the food service is not great (but is a good school for many other reasons). Her friends don’t seem to be exercisers, though my D works out when at home. </p>
<p>West coast girl works out with her friends, has become much more appearance focused in her college years. Food service is better, healthier at her school. Both have taken to cooking for themselves to save money and eat better. They are quite different in weight. Friends ask me if twin A feels badly in comparison. She doesn’t, as far as I know. We live in a very accepting of personal difference sort of town. </p>
<p>Some of this is personal choice, some metabolic difference. Much, I feel, is different campus environment, and the culture of various friend groups. I also wonder about drinking, and how the calorie load from alcohol can affect metabolism of someone with a tendency toward weight gain.</p>