Long ago, while writing my first book, Fight Fat after Forty, I wrote a silly little poem to drive home the point that eating too late and too much each night can contribute to weight gain – “If you eat after eight, you’ll gain a lot of weight”. OK, so there’s no real magic with eight o’clock per se, but it rhymed with weight so I went with it. I was just trying to emphasize that meals need to be carefully spread out over the day, and that it was optimal not to eat at least 1-2 hours before going to bed. Also, it was my clinical observation that when people overate, the evening hours were more potent in packing on the pounds in comparison to the daytime hours. Over the years, studies have supported my experience. Happily, a new study from a Northwestern University team has added further fuel to the fire by showing that overeating in the nighttime does indeed appear to significantly increase your risk for putting on the weight.
Specifically, these researchers found that the time of day you eat is a powerful predictor for weight gain. In a novel experiment, two groups of mice were fed the same high fat diet, which was deliberately intended to cause weight gain. One group of mice ate the diet during the night hours when rodents tend to naturally forage for food. The other group was only allowed access to the food during the daytime hours, when mice classically rested and slept. Extrapolating to humans, this is analogous to overeating the same number of high fat calories either before or after 6:00 PM. The investigators were shocked by the remarkable difference in weight gain between the two groups of mice. The group that simply overate during their typical eating schedule had a 20% weight gain. But the mice who overate the same number of calories during what would have been their sleep time, had a whopping 48% increase in weight. That’s over twice the weight gain of the other group. This is an eye opening discovery.
Now for the $60,000 question – why does it matter when you eat those calories? Scientists are just beginning to piece together this puzzle. Many of us agree that part of the answer lies in understanding how this overeating interacts with a disruption of the normal sleep-wake cycle. During this cycle, it’s believed that there is a complex interplay of brain and body hormones and chemicals that maintain a delicate balance of appetite, hunger and satiety. These, as well as other factors involving daily changes in core body temperature, energy levels and sleep, also play integral roles in metabolism and storage of the food we eat. It doesn’t take a rocket scientist to realize how much 21st century living has disrupted normal sleep-wake cycles. Electricity prolonged our awake hours, and what I refer to as our “weapons of mass distraction” – TV, phone, computers, blackberries – are obliterating any attempts to rest or sleep. You see the problem. Our normal nocturnal biology has been thrown into chaos. And we’re wearing the consequences of these nighttime trips to the fridge.
There are two patterns of nighttime overeating. The first involves “saving up” your calories by skipping meals and snacks and eating the majority of your calories in the evening. The second is to eat above and beyond your calorie budget (with either healthy and/or unhealthy foods) and to do this primarily in the evening. This can take place in a number of ways – grazing all the way to bedtime; eating a large dinner with or without after dinner grazing; eating an average dinner and then overeating after dinner. Do any of these patterns sound familiar? Regardless how you do it, the end result is weight gain.
What’s the solution? For either pattern, the blueprint is the same. Starting with breakfast, eat every 3-4 hours through dinner. Try not to finish dinner later than 8:30PM. I know, life’s challenging, so just do the best you can. Try not to eat anything for at least an hour (ideally two) before going to bed. If you ate dinner early (e.g. 6:00 PM) and you’re not going to bed until 11:00 PM, have a 100-150 healthy snack (e.g. yogurt) say around 9:00 PM, which leaves two hours before you go to bed. Or, you can opt to have a treat at this time (e.g. 100 calorie chocolate mousse bar), understanding that it doesn’t contain much protein and may not be as filling. Use trial and error to see what works best. You can mix them up throughout the week.
If you’re coming home late, just remember that you need to keep up with your healthy snacks to tide you over (grab those nuts you packed in your purse or brief case) so you don’t overeat when you do have dinner. Here’s another one of my sayings: “The later you eat, the lighter you eat”. If you’re stuck eating later, opt for lots of filling veggies and 4 (women) -6-8 (men) ounces of lean protein. That’ll satisfy you and not pack on extra weight. The key is to try not to let more than 4 hours go by without having a balanced meal or snack. Timing is so important in helping you stave off raging hunger and appetite.
Hey, and don’t forget to get enough sleep! Studies show that folks who don’t get 7-8 hours of sleep tend to have much more difficulty eating and exercising appropriately. Do whatever you can to get those zzz’s.
The bottom line is that excellent nutrition is about quality, quantity and frequency of eating. Now we have new respect for the power of those evening hours to either make or break our attempts to finally shed that weight… and keep it off.