Let’s say you’re cutting to get ripped for summer. Should you avoid eating late at night? After all, old rumors say that fewer calories are burned before going to bed. Are they true?
1. Whether you gain weight is a matter of calories: if you consume more calories than your daily energy needs, you will gain fat mass.
2. Energy consumption is a 24-hour story: even at night your body uses a lot of energy, especially BMR, the energy you use per day at rest, for primary life functions such as breathing and your heartbeat.
3. Human research has found no convincing evidence for the claim that calories weigh more in the evening. And that you would therefore gain weight more easily in the evening. Prominent figures such as Brad Schoenfeld therefore speak of a diet myth. In short: a calorie is a calorie.
4. One explanation for the link between eating in the evening and weight gain is the tendency of late eaters to eat more calories in general. This is because you are hungrier in the evening than in the morning. So it is important not to snack too much in the evening and lose sight of your energy balance.
5. When you are cutting you should actually be tracking your calorie intake daily with a calorie app. But this is something that few gym goers are willing to do (for a long time).
HOW DOES FAT LOSS WORK?
Whether you gain or lose fat mass is basically a matter of calories: if you eat more calories than your daily energy requirement you gain fat mass, if you eat less you lose weight. It’s that simple.
ENERGY REQUIREMENT
How this energy requirement, also called energy balance, is structured, you can read in this article. In it you will see that a large part of the energy consumption (50 to 70%) consists of BMR (Basal Metabolic Rate). This is the energy (expressed in calories) that you use per day at rest, or for primary life functions such as breathing and your heartbeat. These functions continue 24 hours a day, even when you sleep.
The other components are the thermal effect of food (TEF: the energy for processing food), spontaneous movement (NEAT: such as blinking your eyes and all kinds of other unconscious movements) and energy expenditure during sports/conscious movement (EAT).
Also important: the energy you consume from food is not digested and stored immediately. It can take 24 to 72 hours for a food to be fully digested.
In short, your body continues to use energy late at night to maintain all bodily functions. Energy needs are therefore a 24-hour story. It is not the case that your metabolism slows down during the evening.
EATING LATE
Traditionally, health gurus too, claim that calories weigh more in the evening, say from eight o’clock onwards, than during the day. And that you therefore gain fat mass faster than during the day, even when you consume the same number of calories. But we have already seen that metabolism is hardly different at night than during the day. So how does it really work?
RESEARCH
The direct reason for our article is a new study on the effects on body composition of eating carbohydrates in the afternoon versus late at night. The outcome shows that the timing of food does not matter; what matters is that you do not eat above your energy needs. And that is in line with the view of muscle growth professor Brad Schoenfeld:
No, eating carbs at night has no greater effects on fat storage than eating them earlier in the day. #ditchthemyth
What about previous research? A selection of human research can be found at Examine.com. There is no convincing evidence that eating late can lead to more fat gain. They conclude:
Eating at night isn’t a factor that will inherently break your diet or compromise attempts to lose weight.
Human studies show that eating beyond your daily calorie needs leads to weight gain, unrelated to what time of day you eat.
So the theory seems to be correct that losing weight is purely a matter of eating below your energy balance and that the time of day does not matter.
In other words: a calorie is a calorie.
BIORYTHM
However, we are not there yet. Losing weight is not only about energy balance, but also about biorhythm, also known as circadian rhythm.
One explanation for the link between eating late at night and weight gain is the tendency of late eaters to eat more calories in general. This is because you are simply hungrier in the evening than in the morning. You may recognize this: not feeling very hungry at breakfast, even though you haven’t eaten all night. The biorhythm seems to be designed to curb hunger at night so that you can rest better.
So it is important that you do not snack too much in the evening, losing sight of your energy balance. When you are cutting you should actually track your calorie intake daily with a calorie app. But this is something that only few gym-goers are willing to do (for a long time).
You can make dieting easier by eating most of your food in the evening, when you are most hungry (after training or not). In the morning and afternoon you limit your food consumption, if desired completely, by intermittent fasting. But even with intermittent fasting it is true that it does not work miracles and that it only helps based on energy balance. So, again, a calorie is a calorie.
CONCLUSION
Losing weight (and thus losing fat mass) is largely a matter of calories in, calories out. If you eat less than your total calorie requirement in a day, you will lose weight. Timing of calorie intake does not seem to matter according to the available scientific research.