Dear Dr. Roach: My adult son has lost over 100 pounds on an intermittent fasting diet (16 hours fasting per day) and now wants to continue fasting in the morning and just eat a heavier lunch and dinner to maintain his new weight. I am not sure that this kind of long-term fasting is good for his health. For his meals, he eats anything he wants and counts his calories. I have told him that it is better for his health if he eats more of a Mediterranean-style diet, which would include a plate made up of mostly vegetables, a small amount of meat, grains and some good fats. Could you advise us what you think is a good way to maintain weight loss after being on an intermittent fasting diet? — G.B.
Answer: Most of the studies on intermittent fasting use an alternate-day approach, where a person takes in very little food (25% of needs) on fast days and more (125%) on the intermittent “feast” day. The studies show effective weight loss, similar to those put on a calorie-restricted diet. There aren’t as many data on a 16-hour daily fast.
My experience is that intermittent fasting is an effective strategy for some people in whom other strategies have been unhelpful. One of my colleagues, an expert in weight loss, calls intermittent fasting another tool in her box.