Research evolving on nighttime snacks

Please help settle a disagreement: Are you more likely to gain weight from eating a snack at night than if you ate the same snack earlier in the day?

You may not realize it, but that is a loaded question.

For years, the standard nutrition response has been “no” — it’s the overall balance between calorie intake and energy outgo that matters, not what time of day you eat.

And that’s still the take of the Academy of Nutrition and Dietetics (formerly the American Dietetic Association). If you go to its website,http://www.eatright.org, and search for “night snack,” you’ll find lots of great guidance, including the notion that eating “late-evening calories are no more likely to promote weight gain than calories eaten at other times of the day.”

But recent studies are beginning to prompt some researchers to reconsider.

Most recently, in a study published in June in the journal Cell, researchers reported findings about two groups of mice fed a high-fat diet. The mice that were fed frequently throughout the day, disrupting their normal nighttime feeding cycle, were more likely to become obese and suffer from related conditions even though their calorie intake was the same as mice fed during normal feeding times. The mice given food only at the “right” feeding time (for mice, it’s natural to eat at night) had better usage of nutrients and expenditure of energy.

A study in the journal Obesity in late 2009 had similar findings: In that study, mice fed only during their natural feeding time weighed significantly less than mice fed at the wrong times. The mice fed at the wrong times also tended to be less active and to eat slightly more than the other group — a bad combination.

The researchers involved in these studies suggest that our eating patterns should adjust to circadian rhythms — that is, you should eat during the day and avoid snacks at night, especially if you want to maintain or lose weight.

Whether or not you accept the researchers’ conclusions, you still might want to consider whether nighttime snacks are the best choice for you. The Academy of Nutrition and Dietetics itself recommends pausing to think if you’re tempted to eat a nighttime snack: Are you eating because you’re hungry, or because you’re bored or anxious, or have just gotten into the habit of having that snack?

Besides, if you’re trying to lose weight, giving yourself a time-related cutoff for eating could help you trim the number of overall calories you consume on a day-to-day basis. It could be a good place to start.

Mindless eating’ leads to weight gain

I try to eat healthfully and normally do well during the day, but in the evening when I’m watching TV, I snack way too much, even though I’m not really hungry. Any ideas?

What you’re doing is so common that it has a name: “mindless eating.” Researchers, especially Brian Wansink at Cornell University, have explored this concept and have found that when Americans eat, we tend to rely not on internal cues, such as how hungry we are, but on other factors. And that leads to overeating.

One of those factors is eating while distracted — when watching TV, talking with family or friends, or eating in the car. When our attention is diverted from what we’re eating, we simply tend to eat and eat and eat — often not even really enjoying the food or the experience of eating it. Research at Yale University shows that viewing television food ads, especially those for unhealthy food, also triggers more food consumption.

Another external factor influencing how much we eat is serving size: If a larger serving is in front of us, we tend to eat more no matter what. Convenience and visibility of a food is another factor — if it’s easy to reach out and grab a food, we’ll be more likely to eat it. Even the way a room is lighted can cause us to eat more: Dim, soft lighting encourages us to prolong the eating experience and we eat more. Still other factors include stress, boredom or emotional reasons for eating.

The kicker? None of this has anything at all to do with how hungry we are.

So, how do you counteract these subconscious influences on eating? That’s a whole other line of study, called “intuitive eating.” Intuitive eating rejects restrictive approaches of dieting. It avoids the idea of “taboo” foods and encourages us to increase our awareness of what our body is telling us related to hunger, cravings and eating behavior. The idea is to actually pay attention whenever you’re eating, pausing to determine your level of hunger versus your feeling of fullness. The idea is to start eating when hungry, no matter what time it is or if others around you are eating or not, and to stop eating when full, no matter if there is more food at hand. Imagine a scale where 1 is starving and 10 is stuffed: Go ahead and eat when you feel like you’re at a 3 or 4 on the scale; stop when you’re at a 6 or 7. It requires thought and self-awareness, but prevents cycles of starving and binging, and also helps prevent emotional eating.

The concept of intuitive eating also lets people eat whatever food they want, as long as they pay attention to hunger/fullness cues. Research shows that such permission also reduces binge eating and is associated with a lower body-mass index.