There seems to be a lot of confusion around the number of meals you should be eating each day to optimize weight loss. Is having 2 to 3 big meals better than 5 to 6 small meals or vice versa?
Common arguments around this topic include that eating breakfast kick-starts your metabolism, spreading your meals throughout the day can reduce hunger and cravings, or that eating right before bed causes weight gain. And what about intermittent fasting?
The truth is that the research shows mixed results and what works for one person may not work for everyone. To help you decide what is right for you, here are answers to the most common questions about meal frequency.
Does Eating Often Increase Metabolism?
In simple terms, your metabolism is the measurement of how efficiently your body generates and uses energy - in other words, how many calories you burn each day.
The biggest determinant of your overall energy expenditure is your basal metabolic rate (BMR) or resting metabolic rate (RMR). This is the minimum amount of calories your body needs to function at rest and accounts for roughly 60 to 70% of your total calorie needs. Your BMR can differ drastically from one person to the next based on age, muscle mass, genetics, overall health, etc. which is why some people can seem to eat whatever they want and not gain weight - it is their naturally fast metabolism.
Exercise or increased activity from moving around, in general, can also add to your calorie expenditure, but this still only accounts for a small portion of your overall output - less than 30% for most people.
So how can eating affect your metabolism?
Well, a tiny portion of your total daily energy expenditure (TDEE) is affected by the type of foods you consume and eating in general. Digesting food requires some work, so the actual act of eating uses up some calories. But the amount is fairly minimal - less than 10% of your daily calories burned (1).
The theory that eating stokes your metabolic flame is way overstated and has not really been shown to be an effective way to promote more weight loss. The amount of calories you consume almost always outweighs the calories you burn digesting.
To put this in perspective, you burn about 11 calories an hour chewing and you use about 10% of calories from a typical meal to digest it (2). So if you ate a 200 calorie meal in 10 minutes (realistically, most people eat much faster than this and don't chew for 10 min straight), you'd burn about 1.8 calories from chewing and an additional 20 calories digesting - 22 calories total. If you eat this meal three times a day you'd burn 66 calories and if you eat it six times a day, you'd cut 132 calories.
However, you have to consider overall calories. Eating six meals a day means you're eating twice as many calories overall - 1200 calories vs 600 calories. And even if you ate the same amount of calories, the differences in calories burned from chewing would be minimal (~1.8 calories for each extra 10 minutes of chewing). So in the end how often you eat doesn't make as big of a difference than overall calories.
Frequent meals and snacks can also mean frequent calories and higher calorie intake overall. And research suggests that eating less frequently may be a better approach to weight management due to improved calorie control (3).
You cannot "wake up" your metabolism with food. It is always going, working to pump blood to your organs and tissues, expand your lungs for breathing, and supplying energy throughout your body for survival. Eating is just one small part of the equation.
There isn't really a way to hack your metabolism to increase it. And how often you eat is not an effective approach to increasing your metabolism. If you really want to increase your calorie burn, adding more muscle mass (aka gaining weight) may be your best bet, as well as increasing your physical activity. But even this approach won't guarantee you a super fast metabolism and free rein to eat whatever you want. Understanding how many calories you need a day to lose weight and sticking to that amount is key.
Do Frequent Meals Reduce Hunger and Cravings?
Some studies suggest that increased meal frequency does not affect overall fat loss and may actually increase feelings of hunger (4,5). And eating less often is associated with improved appetite control in a number of studies (6,7).
However, there may be a difference between overweight and lean individuals when it comes to meal frequency and appetite, as well as overall fitness and activity level (8). One study looking at lean males suggested smaller, more frequent meals might help control appetite better (9).
The type of food you eat can also strongly impact hunger levels. Several studies have examined the effects of eating more high sugar foods and refined carbohydrates on increased appetite (10). And more recent research emphasizes the importance of nutrient dense, whole foods - especially high protein foods, for better hunger management and overall weight loss (11,12,13).
There are a number of factors that can influence appetite and how often you eat might be one of them. However, the best approach can differ from one person to the next. The research is also slightly stronger when looking at the type of food you are eating compared to how many times per day you eat in controlling appetite and calorie intake overall.
Does Eating Before Bed Cause Weight Gain?
It is commonly thought that eating a large meal right before you go to bed is going to cause you to gain weight or store more fat. After all, eating a big bowl of pasta and then sleeping it off can't be good for you... right?
Well, the thing is your metabolism doesn't shut off just because you went to bed. And your body is going to use whatever energy you provide it, no matter what time it is - as long as you aren't going over your daily calorie needs.
However, some studies do suggest that those who tend to eat later at night, tend to consume more calories overall which can lead to weight gain (16,17,18). And late night eaters tend to make poorer food choices (19).
Weight gain aside, eating a larger meal before bed can also cause indigestion and may disturb your sleep routine (20,21). While some foods will affect this more drastically than others, if you're having acid re-flux late a night, eating large meals before bed could be the culprit.
The best time to eat dinner depends on your overall daily intake and when you are hungry - it really boils down to personal preference. If you have a hard time controlling your calorie intake during the day, sticking to a set schedule and eating smaller portions instead of larger meals at night may help. And if you tend to crave unhealthy foods at night, opt for nutrient dense snacks over a full meal if you need to eat late, and eating more calories earlier in the day. eating smaller portions instead of larger meals
Why Is Breakfast So Important?
Some research suggests that eating a large breakfast and smaller lunch and dinner, in addition to less snacking and fewer meals overall, may promote better weight management due to improved appetite throughout the day and decreased calorie intake (22,23,24).
In addition, having a large breakfast may support blood sugar control. In one study diabetics who ate more calories earlier in the day had better blood sugar control throughout the day (25).
But what you eat for breakfast could be just as key as a large meal itself. In one study, participants who ate a high carbohydrate and protein breakfast reported less hunger and cravings in a calorie deficit (26). And high protein breakfasts have long been associated with better weight management (27,28,29,30).
A good amount of research continues to associate larger breakfasts with improved appetite throughout the day, blood sugar control and better calorie control overall. These effects are most strongly seen with high protein breakfasts and quality food choices.
Skipping Meals: Good or Bad for Weight Loss?
What about skipping meals or using fasting as an approach to cutting calories and weight loss? For years we've been told that skipping meals is going to mess with our appetite and energy levels and cause us to overeat at our next meal, but is this true?
The truth is, there isn't a large amount of research suggesting that skipping meals leads to poor appetite control and it likely depends on the person.
Effects could also differ based on the meal you skip. Skipping breakfast was more strongly associated with higher body weights than eating before bed in one study (31). But another study indicated no difference between which meal is excluded, as long as the overall intake is controlled (32).
Establishing consistency is also a major factor. If you eat at the same time every day and skip a meal, your appetite may be much more affected than if you regularly skip the same meal throughout the week. In other words, systematizing your diet and following a routine could be an important component in managing hunger and calories (33). And what works for one person doesn't work for everyone.
There are a few potential benefits to strategic fasting and meal skipping.
Intermittent fasting may help with weight loss by limiting your eating window to a specific time of day, and by result reducing your overall calorie intake. But outside of calorie control, fasting or skipping meal has not been shown to be more effective than other meal frequencies (34,35). Some research also suggests that periods of fasting can not only help you control calorie intake but may also improve your health (36,37,38).
Skipping meals or intermittent fasting might be an effective approach to cutting calories if you don't make up for the calorie deficit at later meals. Establishing a routine is also key in helping you manage appetite and stay on track.
Maintaining daily calorie control likely remains the best approach to weight loss regardless of how many meals or when you eat.
But it may also be worth considering the following:
- Eating more calories earlier in the day may be a beneficial approach to losing more weight (39).
- High protein, nutrient dense foods might promote better appetite control.
- Establishing a pattern or eating routine is key for managing calorie control and hunger.
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