When you eat is not as important as how much you consume or the foods you choose to enjoy. Your body does not store more fat at night -- or any time or hour of the day. And your metabolism does not slow down in the evening hours. Weight gain (and loss) is more directly affected by what you eat and how much.
It’s one thing to make a claim, and it’s something completely different to prove it. That's why Israeli researchers decided to test the myth that eating at night led to more weight gain. What they found was groundbreaking for anyone who believes that eating after 7 pm will make you fat.
In the 6-month study, the scientists compared people who ate their most substantial meal at breakfast to those who ate their largest meal at dinner (8 p.m. or later).
The results: the late-night eaters lost more fat than the people who ate a big breakfast. And it wasn't insignificant either; they lost an average of 10.5% more body fat.
And that was just the start of the interesting results that turned diet folklore on its head.
When the dust settled, the research offered evidence that late-night eating isn't your weight loss enemy. And it wasn’t just one study. Other studies have found that people who eat 70 percent of their calories after 7 p.m. (compared to eating more calories earlier in the day) preserved more muscle mass and lost more body fat.
So how did this belief spread? It's a classic story of how one story creates multiple nutrition practices based on very little proof.
The Metabolism Myth
Before you question why late-night eating doesn't actually make you gain weight, it's important to understand how your body processes calories.
Every time you put food in your mouth, you burn calories. This process is known as the “thermic effect of food” (or TEF). When you eat, your digestive machinery works hard to break down the food and convert the food into energy. This “food energy” is what helps you do everything from walking and thinking, to breathing, building muscle, losing fat, and even sleeping.
Of all the foods you eat, protein is the most metabolically expensive—your body needs more energy to break down, digest and put protein to use than either carbohydrates or fat. You burn up to 30 percent of the calories you eat from protein are burned during the digestion process. So, that means if you eat 100 calories from protein, only 70 calories might “hit” your body.
That’s one of the main reasons why protein (or taking whey or plant protein powders) is so essential in any diet; the more protein you eat, the more calories you burn. Carbohydrates are less metabolically active (about 6 to 8 percent burned), and fats are the least metabolically active (about 4 percent burned) despite being the highest in calories and great for your testosterone levels.
Because we know that we burn calories when we eat, some nutritionists assumed that eating first thing in the morning -- and therefore squeezing in more meals into a day -- would lead to your metabolism working harder and burning more calories.
The reality is that your body doesn’t care about how many meals you eat. You can choose how often you want to eat every day. More importantly, your metabolism isn’t dependent on when you eat, but rather what you eat.
The thermic effect of food is directly proportional to caloric intake and the foods you eat, and if the caloric intake and food choices are the same at the end of the day, there will be no metabolic difference between eating six meals or three. Or eating a big breakfast, a small breakfast, or breakfast at all. The same goes for the size of your dinner.
The bottom line: when you have your meals does not directly influence weight gain.
Should You Eat at Night?
Many people eat at night out of boredom or because of emotions such as stress or anxiety, and that’s how "innocent" nighttime eating can turn into binge-like behaviors.
When in doubt, always remember that calories matter. It’s like a bank account. You only get so many calories per day, and it’s up to you to choose when you spend them. That’s why personality and behavioral factors are so important. If you’re a night eater that’s fine, but remember to eat less earlier in the day.
While eating carbs at night can potentially help you sleep, you need to be mindful of how bigger meals make you feel. If you find that eating more makes it harder to fall asleep, you might want to change your approach.
Researchers from Wake Forest University discovered how not sleeping enough can impact hunger and weight gain. People who slept 5 hours or less each night gained nearly 2.5 times more abdominal fat than those who logged 6 to 7 hours.
If you've found that eating too much turns you into a bottomless pit or it makes it hard for you to sleep, then smaller meals at night might be the best bet for you. If not, you can choose when you want to eat your largest meal, even if it means eating more in the evening.
People with a “sleep deficit” tend to eat more (and use less energy) because they’re tired, say the researchers. And if you’re sleep-deprived and not just tired, University of Chicago researchers report that lack of sleep can torpedo weight loss by slowing your metabolism, increasing your appetite, and decreasing the number of calories you burn.
Whatever you choose, know that the best option for you has much more to do about lifestyle preferences and behavioral triggers than the fear of eating at a particular time or consuming a specific food.