Does skipping breakfast make you fat or thin?


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I should state my bias up front: I’m a big believer in the importance of breakfast, fully indoctrinated by my mother from a very young age. So when I saw this press release, my skepticism ramped up to full power. It describes a new study in Nutrition Journal (full text available here) that analyzed the diets of 280 obese and 100 normal weight subjects for 10 to 14 days, concluding that eater a bigger breakfast led to greater overall caloric intake for the day:

Therefore, overweight and obese subjects should consider the reduction of breakfast calories as a simple option to improve their daily energy balance.

Heresy! Or is it… I decided I should at least read the paper. It turns out this is, indeed, a long-running debate. The authors of the new study, from the Else-Kröner-Fresenius Center of Nutritional Medicine (in Munich, where compound nouns are a way of life), argue that previous studies have been guilty of what seems like a fairly obvious error in interpretation. These previous studies have found that the higher the proportion of your daily calories you get at breakfast, the lower your overall caloric intake is that day. But these results are skewed by days when people choose to have unusually small lunches and dinners, the new study argues.

The details of this statistical debate are fairly intricate — and not that interesting, actually. Because the strongest arguments for breakfast were never predicated on the theory that you’d eat less later. It’s the other side of the energy balance equation that’s more interesting. By taking in the calories at the start of the day, you’re getting them right when you need them, rather than later when your physical activity for the day is done. You’re also getting your body out of starvation mode so that you’ll choose healthier foods and not store everything as fat when you finally cave in and have some food.

So what are the long-term effects of skipping (or not skipping) breakfast? A study in December’s American Journal of Clinical Nutrition followed 2,184 Australian kids back in 1985, and then checked in again in 2004-2006. The study looked for the effects of skipping breakfast as a kid, an adult, both, or neither. The results:

[P]articipants who skipped breakfast in both childhood and adulthood had a larger waist circumference and higher fasting insulin, total cholesterol, and LDL cholesterol concentrations than did those who ate breakfast at both time points.

Now, you might say that the people who skipped breakfast also happened to be Very Bad People in other aspects of their health. That’s a fair point — though the researchers do at least try to account for the possibility that the breakfast-skippers were eating trash for the rest of the day:

Additional adjustments for diet quality and waist circumference attenuated the associations with cardiometabolic variables, but the differences remained significant.

If you’re still not convinced, consider this final salvo, from the European Journal of Clinical Nutrition in September. Researchers at King’s College London analyzed the breakfasts eaten by 60 kids, then gave them a battery of cognitive tests. Now, it’s old news that breakfast makes you smarter. The new wrinkle in this study is that they broke the data down into four groups depending on glycemic index (how quickly sugars will enter the bloodstream) and glycemic load (glycemic index times portion size). The results weren’t entirely straightforward, but the best option seemed to be a low-GI, high-GL breakfast — in others words, have a big breakfast but make sure it’s not just a bunch of sugar and refined cereal or bread.

Last point: this isn’t carte blanche to totally ravage the breakfast buffet. In the study that sparked this post, one of the foods that contributed most to breakfast calories was cake (51 cal for the obese group, 132 cal for the normal group!). I mean, come on! If the Else-Kröner-Fresenius folks are advocating skipping breakfast to lose weight, then I heartily disagree. But if they’re just suggesting that you should go easy on the cake and sausages, then yeah, that sounds like pretty good advice — at any meal.

14 Replies to “Does skipping breakfast make you fat or thin?”

  1. I’m also a firm believer in eating breakfast. It jump starts my metabolism and decreases my cravings. However, eating breakfast isn’t a magic bullet for weight loss, you have to make healthy choices at breakfast as with any other meal.

  2. Thanks for the article. I enjoy reading your blog, I’m usually not much of a commenter but I couldn’t help myself with this one! As someone who doesn’t eat breakfast, it spurred me onto doing a bit of research so that I could try and weigh up whether my current eating practices are anything to worry about. I realise that the overall tone of the article was a bit light-hearted but I’m choosing to respond to some of the points at face value for the sake of the exercise…

    “By taking in the calories at the start of the day, you’re getting them right when you need them, rather than later when your physical activity for the day is done.”

    I didn’t think people actually put much weight on this argument, whether you gain or lose weight will be mainly attributable to one’s 24hr energy balance, not what time of the day food is consumed.

    “You’re also getting your body out of starvation mode so that you’ll choose healthier foods and not store everything as fat when you finally cave in and have some food.”

    Can you really say that the body goes into ‘starvation mode’, after ten hours of not eating? I was under the impression that the negative effects of fasting come into play a lot later down the track. Also, the choices of food would have little effect on whether fat is stored or not, again it’s the individual’s 24 hour energy balance which matters. The research I’ve come across seems to show that meal frequency has very little effect on body composition, if you’ve got some studies that show that skipping one meal significantly increases fat storage I would definitely need to read them! Studies on alternate day modified fasting seem to indicate that it is an effective method for weight loss, which also doesn’t fit in well with the ‘starvation mode’ concern.

    I can see that skipping a meal once in a while might lead you to some poorer food choices once hunger sets in. However, I find hunger signals adjust fairly quickly to whatever meal patterns you choose, providing that they are at consistent times every day. Martin Berkhan from mentions a study by LeSauter et al. (2009) about ghrelin secretion which would seem to support this.

    The AJCN paper definitely was thought provoking in its results, but it is still an uncontrolled observational study. I know they say they adjusted for diet quality and waist circumference, but there are still way too many unknowns.

    The last breakfast study you referred to compared different types of breakfast, not whether breakfast was eaten or not. You say that “it’s old news that breakfast makes you smarter” but I’m not sure that the effects are as well pronounced as you imply, once you control for things like nutritional status. A recent systematic review by Hoyland et al. (2009) did conclude that breakfast had positive effects on cognition; however they report that these are more pronounced in children that are somewhat nutritionally deficient. They note that studies in the area are poorly designed and mainly funded by industry.

    So, I think for the time being I’m not going to worry too much about missing breakfast. I’m not anti-breakfast by any means, maybe as more research shows up I’ll reconsider my habits. I just think that it is less important than other factors like overall energy and nutrient content and the regular timing of meals (whenever they may be). In some cases such as when using intermittent fasting approaches, skipping some meals can be an effective means for weight loss. For me, the main benefit is being able to get ready in time for work!

    Hoyland, A., Dye, L. & Lawton, C.L., 2009. A systematic review of the effect of breakfast on the cognitive performance of children and adolescents. Nutrition research reviews, 22(2), pp.220-43. Available at: [Accessed October 22, 2010].
    LeSauter, J. et al., 2009. Stomach ghrelin-secreting cells as food-entrainable circadian clocks. Proceedings of the National Academy of Sciences of the United States of America, 106(32), pp.13582-7. Available at:

  3. Thanks for the fantastic post, Scott! Tons of great info in there, and I appreciate you digging up all the that research — and calling me out on the places where my impassioned defense of breakfast was on thin ice. 🙂 The truth is, when I read that first study, I thought it would be simple to pull up some solid research showing how wonderful breakfast is. But it was tougher than I expected, and your post reinforces the controversies in this field of research. Having said all that, in the spirit of the original post, let me take another crack at defending breakfast’s honour:

    “whether you gain or lose weight will be mainly attributable to one’s 24hr energy balance, not what time of the day food is consumed.”

    Of course 24hr energy balance is the prime driver. But is it certain that time of day doesn’t play a role? There’s evidence that glucose tolerance decreases in the evening, and insulin resistance rises, which is one of the reasons night-shift workers have so many health problems. Also, here’s a 2010 PNAS study (in mice, I’ll admit) that found “significantly increased body mass and reduced glucose tolerance” in a group of mice who (because of lighting conditions) took in a higher proportion of calories than usual during the day (which is their equivalent of night, when they’re less physically active). They ate the same total number of calories as regular mice, and got the same amount of physical activity; it was just the timing of eating that changed: “Restricting food consumption to the active phase [i.e. night for mice, day for humans] in DM mice prevents body mass gain,” the study concludes.

    “The research I’ve come across seems to show that meal frequency has very little effect on body composition…”

    Agreed — but most of the research that I’ve seen focuses on adding extra meals, not subtracting one. Here’s a 2011 Journal of Nutrition review that concludes: “increased eating frequency (>3 eating occasions/d) has minimal, if any, impact on appetite control and food intake, whereas reduced eating frequency(<3 eating occasions/d) negatively effects appetite control."

    Here’s another study that compared two meals to three meals per day and found differences in the pattern of fat oxidation: “Eating three meals compared with two meals increased 24 h fat oxidation, but decreased the amount of fat oxidised from the breakfast.”

    Neither of these comes close to proving that breakfast is essential, of course — but it suggests that it’s not crazy to hypothesize that the timing of eating, even on as short a timescale as short as 24 hours, affects substrate partitioning.

    “A recent systematic review by Hoyland et al. (2009) did conclude that breakfast had positive effects on cognition; however they report that these are more pronounced in children that are somewhat nutritionally deficient.”

    I think this is a classic example of the habit that I was gently mocking (in myself) in the original post: we all tend to interpret studies in light of what we already believe. You write the above line to suggest that breakfast isn’t such a big deal for cognition, because the effects are bigger in hungry kids. To me, the news is: yes, they found an effect. As an adult who’s generally pretty well fed, the effect will be much smaller in me — but I’ll scratch and claw for every extra IQ point I can get!

    Bottom line: my faith in the healing powers of breakfast is a lot shakier than it was 24 hours ago. As Scott shows, it’s perfectly possible to make a strong case that breakfast isn’t that crucial. But if anyone asks my advice, I’m still going to claim that it’s the most important meal of the day!

  4. Same to you, Scott — your post made me rethink some ideas I’d taken for granted. (And just between us, if I was evaluating the evidence for breakfast by the same standards I evaluate the evidence for supposed ergogenic aids, I’d have to conclude the evidence is too flimsy to suggest that anyone should change their habits if they’re doing fine.)

  5. I never used to eat breakfast and I was always are 6′ 220 pounds. Because I’m always on the go or trying to sleep as late as possible, I don’t have time for solid nutritious breakfasts. However, over the last 8 weeks I have started drinking a protein shake within 30 minutes of waking and I’m down almost 20 pounds. I feel amazing during the day and look forward to my morning shake.


  6. I’m suprised no one has done the obvious study: calorie intake for people who eat two meals a day vs. those that eat three. And for the life of me, I can’t find a study on skipping breakfast as a strategy to lose weight.

    Yes, overweight people tend to skip breakfast more. However, maybe overweight people are skipping breakfast as an attempted weight loss strategy. If so, then the study is simply saying that overweight people are ones that tend to diet. Duh!

    I am a regular breakfast eater, but I’m going to skip it as a weight loss strategy. Why? My love for breakfast sandwiches has not been kind to my waist line. Also, I find that I’m just as hungry for lunch as I was if I ate breakfast. Without a study that clarifies the question of skipping breakfast as a weight-loss strategy, it will be difficult to disern if my success (or lack of it) is anecdotal.

  7. I think it’s kinda right. When I don’t eat breakfast, I don’t really eat much else for the rest of the day and so I’m not consuming a lot of calories. It’s often just snacks and a meal. The overal intake of calories can be as low as 800. However, when I eat breakfast (a typical breakfast such as toast or cereal) I end up hungry only a few hours later and needing to eat again, and again, and again. The breakfast really does “kick start” your digestive system so I guess your body needs to eat to get enough calories to digest your food? I dunno. However, when I eat a really fatty, junky breakfast such as bacon & eggs, I don’t get hungry as quickly. I’m not sure what I’m trying to say here, all I know is that I don’t have the best diet and rarely eat breakfast, but I’m not obese.

  8. I just wonder if I am a freak or what. I’ve always been a breakfast-skipper and for the most of my life I had around 100 lbs. More than once I tried to introduce breakfast into my daily routine (because I am trying to be a nice girl and listen to what doctors say), and every time I added a couple of lbs (once I even added 20 in no time!). As soon as I begin skipping my breakfast, I just lose all the surplus, even if I eat giant suppers. Also, breakfast makes my brain sleepy and lazy and I am just useless. So in the end I gave up and resigned myself to the fact that I was just not born to eat my breakfast. Other than that I am a fan of healthy living. Conclusion? No conclusion. Just wondering.

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