You’ve probably heard the common adage that light snacking is a smart dieting strategy, preventing you from getting too hungry and going overboard at your next meal. But in truth the research has been inconclusive, with some studies supporting snacking and others suggesting that munching between meals promotes weight gain rather than weight loss. Now new research suggests that timing could be key to whether snacks help or hurt when dieting.

Postmenopausal women who were overweight or obese were instructed to consume between 1,200 and 2,000 calories per day, with the exact figure depending on each woman’s starting weight…and to keep daily food diaries, noting what they ate or drank and when. Participants also received nutrition counseling but no specific advice on snacking and meal make-up.

At the end of the yearlong study, researchers found that snacking was nearly universal, with 97% of participants reporting having at least one snack per day and upwards of 80% having more than one snack per day. Surprisingly, the frequency of snacking didn’t matter—what did make a difference was the time of day when snacking occurred. Results…

  • Midmorning (10:30 to 11:29 am). Women who regularly allowed themselves a midmorning snack lost an average of 7% of their body weight—while those who did not snack between breakfast and lunch did much better, losing almost 12% of their body weight, on average.
  • Midafternoon (2:00 to 5:29 pm). Women who snacked between lunch and dinner lost slightly less weight than women who did not snack at this time. Curiously, though, the afternoon nibble conferred nutritional advantages, with these snackers consuming significantly more fruits, vegetables and fiber than women who did not snack in the afternoon.
  • Evening (9:00 pm to midnight). After-dinner snackers lost a little bit more weight than those who skipped the evening snack. (Researchers declined to speculate on the reason for that.)

Why was the midmorning munch a problem when snacking at other times of the day was OK? Researchers suggested that, since there are usually only a few hours between breakfast and lunch, women who snacked in the morning did so not because they were actually hungry, but because they were bored and eating gave them something to do…or because they wanted to socialize (coffee and a quick bite, anyone?).

For better dieting success: Declare the morning hours a snack-free zone, and limit your snacking to afternoon and/or evening. Snack only when you’re truly hungry, and then stick with proteins, such as low-fat yogurt or a small handful of nuts…fruits and nonstarchy veggies…whole grains…or calorie-free drinks, such as coffee or tea.