Should You Skip Breakfast?

Will skipping “the most important meal of the day” help or hurt your weight loss?

Science, avocado toast… this is happening.

It’s a cliché we’ve heard a thousand times: “breakfast is the most important meal of the day.” And while some people still push the bacon-wrapped agenda of eating breakfast like a king, lunch like a prince, and dinner like a pauper, not everyone follows or believes this “sage advice.”

Luckily, science doesn’t follow tradition — and we love the smell of science in the morning. Let’s look at how breakfasts big or barren can affect weight loss, muscle gain, and even sleep.

The Science of Skipping Breakfast

When scientists observe what people naturally do (not trying to change their behavior) they see conflicting outcomes. Some research suggests that breakfast skippers tend to have a higher body mass index (BMI), which is the ratio between height and weight that determines whether you’re underweight, normal, overweight, or obese [1]. Higher BMIs would be a problem, but other research found no relationship between breakfast and BMI [2].

And it’s not uncommon to get such opposite findings when it comes to breakfast, making it hard to really answer the question: to skip or not to skip? Other scientists have suggested that it depends on your body composition. One study found that overweight children who skipped breakfast tended to decrease their BMI, while normal-weight children who skipped breakfast increased their BMI [3].

Luckily, we don’t have to rely just on observations when laboratory-based research can control the variables that make these studies so confusing. One controlled study found that skipping breakfast had no effect — good or bad — on energy expenditure or metabolism [4]. Another compared different types of breakfast to no breakfast, and again there were no differences in metabolism or health markers [5], but this time the no-breakfast group lost more weight than the other groups. These studies make it clear that, while some observational studies imply that skipping breakfast could cause weight gain, this doesn’t seem to be true.

The Anti-Breakfast Benefits

And this makes perfect sense. Because, whether you’re trying to lose weight or gain weight, total calorie intake is the key factor. You could use any “magical” nutrient timing strategy in the world, but if you’re eating fewer calories than you burn, you’re losing weight, and if you eat more than you burn, you’re gaining weight.

That means that, if you’re trying to decide whether to eat or skip breakfast, you have to view that decision in the context of how much food you’re going to eat. And that’s where the science can be more helpful.

One study looked at how eating different breakfasts (high-carb vs high-fiber) or no breakfast at all would affect the amount of food you eat later, at lunch [6]. The results aren’t surprising: skipping breakfast probably makes you hungrier at lunch time. However, even if you end up eating a slightly larger lunch, the researchers found that this wouldn’t make up for the calories you missed at breakfast. For example, if you skip a 600-calorie breakfast, then “overeat” at lunch by an extra 200 calories, you’ll still be in a 400-calorie deficit. This could make skipping breakfast a useful strategy for reducing energy intake and achieving weight loss.

This starts to sound a lot like intermittent fasting — a practice that’s become increasingly popular in recent years. The basic idea is to set restrictions on when you can eat food, such as a 4–8-hour window in the day. This effectively keeps you from eating for 16–20 hours per day. While proponents will cite lots of reasons why you should fast, there are really two big benefits you should care about. First, you might find that taking time away from meals (like making and eating breakfast) saves you time and energy in your day. Second, because you’re eating less often, you get to eat substantially larger meals, which could be more satisfying.

Outside of changing the total calories you eat, none of this makes a difference in weight loss. But it could be a useful lifestyle trick to keep you on task and keep food off the brain. You’ll be hungrier later, but you get to eat more food — the choice is yours!

… And the Downsides

Just like calories, the total amount of protein you get each day is important. While calories control the amount of weight you lose, protein decides how much of the weight lost is fat and how little of it is muscle.

And this is where skipping meals, including breakfast, can present a problem. Because, while total protein matters most, how we distribute that protein through the day can still make a difference.

When we eat protein, we boost muscle protein synthesis (the muscle-building process) and suppress protein breakdown (the muscle-eating process). Eating one or two big, high-protein meals can get us to our total daily need, but the benefits may not be as strong. Despite what you might’ve heard, there’s no firm “limit” to how much protein we can absorb in a meal [7], but there are diminishing returns. The more protein we eat at one time, the less efficiently our body processes that protein.

That’s why current recommendations say to spread daily protein out across 4–5 meals [7,8]. Skipping breakfast takes away a big opportunity for protein early in the day, and if we restrict the “feeding window” through intermittent fasting, those protein meals dwindle. So, while blazing past breakfast could help with weight loss, it doesn’t bode as well for muscle gain.

Here’s another small problem: circadian rhythm. This rhythm is our body’s internal clock, which governs the patterns of waking and sleeping that keep us happy and healthy. If we skip breakfast, we’re passing by what might be an important marker that helps our body stay in sync. In fact, there’s growing evidence that shifting calories later in the day could have negative effects on metabolism [9] and sleep quality [10]. If you want to bolster your circadian rhythm, it makes the most sense to eat periodically while the sun is out and stop eating after it sets. But, as we’ve already seen, fasted mornings aren’t going to stand in the way of weight loss or trash your metabolism.

Science Brunch: The Best of Both Worlds

The science behind eating breakfast is limited and at odds with itself, but we do know that skipping breakfast won’t make or break you. So, it looks like flexible dieting wins again! Because the truth is: It’s all up to you and your goals. Want to lose fat? Skipping breakfast looks like a practical choice. Want to gain muscle? At least get some protein in after you wake up. If eating early is part of your lifestyle, there’s nothing telling you to change, but if you prefer to power through till lunch, then more power to you.

References

1. So HK, Nelson EA, Li AM et al.: Breakfast frequency inversely associated with BMI and body fatness in Hong Kong Chinese children aged 9–18 years. Br J Nutr. 2011;106(5):742–51.
2. Williams P: Breakfast and the diets of Australian children and adolescents: an analysis of data from the 1995 National Nutrition Survey. Int J Food Sci Nutr. 2007;58(3):201–16.
3. Berkey CS, Rockett HR, Gillman MW et al.: Longitudinal study of skipping breakfast and weight change in adolescents. Int J Obes Relat Metab Disord. 2003;27(10):1258–66.
4. Kobayashi F, Ogata H, Omi N et al.: Effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose. Obes Res Clin Pract. 2014;8(3):e201–98.
5. Geliebter A, Astbury NM, Aviram-Friedman R et al.: Skipping breakfast leads to weight loss but also elevated cholesterol compared with consuming daily breakfasts of oat porridge or frosted cornflakes in overweight individuals: a randomised controlled trial. J Nutr Sci. 2014;3:e56.
6. Levitsky DA, Pacanowski CR: Effect of skipping breakfast on subsequent energy intake. Physiol Behav. 2013;119:9–16.
7. Schoenfeld BJ, Aragon AA: How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018;15:10.
8. Jager R, Kerksick CM, Campbell BI et al.: International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
9. Tahara Y, Shibata S: Chronobiology and nutrition. Neuroscience. 2013;253:78–88.
10. Crispim CA, Zimberg IZ, dos Reis BG et al.: Relationship between food intake and sleep pattern in healthy individuals. J Clin Sleep Med. 2011;7(6):659–64.
11. Garaulet M, Gomez-Abellan P, Alburquerque-Bejar JJ et al.: Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond). 2013;37(4):604–11.
12. Jakubowicz D, Barnea M, Wainstein J et al.: High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Obesity (Silver Spring). 2013;21(12):2504–12.