Is a Carb a Carb?

Are 50 grams of sugar more fattening than 50 grams of rice? Are whole grains always better than refined grains? Should you limit your fruit intake to avoid fructose overconsumption? Sure enough, not all carbohydrates are created equal. There are many methods in use to classify carbs and even terms for specific kinds of carbs.

Take sugar for example. Sugar is widely believed to be excessively fattening. That is, many people believe that calorie per calorie sugar is more fattening than other carbs. Others point out all carbs end up as glucose in your body and cite the truism that a calorie is a calorie. Those arguments are often countered by theories involving insulin and the ‘a calorie is a calorie’ slogan doesn’t mean all calorie sources have the same effect on your body composition. Foods differ in their effects on your metabolism and their ease of absorption, which is one of the reasons why protein is less fattening than fat, calorie per calorie.

Rather than having a theoretical debate on the issue, which seems to be what most people in the fitness industry like to do, I’d rather just look at the empirical facts. People know me as an academic, but I’m also a pragmatist and I ultimately only care about results. Since I’m mainly interested in bodybuilding, I will look specifically at the effects of different types of carbs on your body composition.

Read the full article on SimplyShredded.

Note: The in-text references were omitted on SimplyShredded, but the order of studies in the references section exactly follows the order I mention them in the text (i.e. the 5th finding I discuss is reference #5).


  1. Martos says:

    Interesting article! One question: isn't there a link between people who eat simple carbs and type 2 diabetes? I remember Walter Willet brought this up in one of his books.

    • Menno Henselmans says:

      Like I referenced in the article, only if you’re already unhealthy. If you’re lean and active, your body can easily handle the glucose and insulin from simple carbs. Observational research has the huge confounding variables of satiety, energy intake and obesity. Sugar isn’t filling, so people tend to overeat it, causing weight increases, causing obesity, causing diabetes.

  2. Tobias says:

    Very interesting read! Thanks Menno!
    Some new feedback:
    Another topic I'd like to read something about would be the negative influences of trans-fats… There seem to be many different opionions how bad the sporadic consume of them can affect fat loss and muscle-building.

  3. Another great article Menno,
    I'm starting to think that a lot of nutritional dogma is somewhat irrelevant (Do not read "Totally irrelevant") to the 'healthy', lean individual who trains 4 or 5 times a week, particularly when most reccomendations (such as complex over simple carbs, Fat is bad etc.) are aimed at obese, sedentary individuals.

    • Menno Henselmans says:

      That’s definitely true in many cases. Obesity and inactivity are just absolutely colossal confounders of the research on health. Almost anything – diabetes, chronic inflammation, cardiovascular risk factors, blood lipids, neurological disorders, etc. – is considerably mediated by obesity and inactivity. Not to mention they’re hugely correlated themselves. Pretty much anything you can do for your health pales in comparison to being fit and lean. The exceptions are often drugs, e.g. smoking will mess you up regardless.

  4. Wouter says:

    Another subject I can stop obsessing about…;)
    Can't wait for more to come.

  5. Tristan says:

    I'm really enjoying your articles. Learning a lot.

  6. Branr says:

    I know the studies say that if you are already “healthy”, eating a higher Glycemic load diet doesn’t negatively affect insulin sensitivity, but I find this kind of hard to believe. What is “healthy”? How long were these studies performed: over weeks or decades? I care about my physique and gym performance, but I care a lot more about overall long term health. It does make intuitive sense that constantly dumping high insulin spikes would, over time, cause your body to either develop insulin resistance, or perhaps be non-beneficial to the pancreas. If there are studies looking at insulin sensitivity over years, I’d love to read them! If there aren’t, I’d call this topic far from conclusive.

    • ‘Healthy’ in these studies often means non-obese and/or recreationally active, so it’s safe to say a serious trainee is healthy by these standards. If you’re healthy, the insulin ‘spike’ isn’t that large because you’re very sensitive to insulin. That’s one of the reasons GI/II doesn’t matter. No RCTs that I know of have spanned for over 2 years, but there is no evidence from cohort studies or real life that GI matters either. Athletes have a markedly reduced lifetime risk of developing diabetes despite shoving down extreme amounts of carbs on a daily basis. More importantly, no accumulating effect takes place all of a sudden after X months. Diabetes develops gradually or it doesn’t develop at all, because glucose homeostasis is an acute process.

      • Branr says:

        Do you think you can explain that last sentence? It flew over my head a bit. Where do you think the whole “high GI carbs cause insulin resistance/type II diabetes” theory came from? Is this true for people who are already diabetic or borderline diabetic? I’ve always been told type 2 diabetes is basically the penalty for eating high GI foods your whole life; your pancreas can’t keep up with the large amounts of insulin it needs to produce to put away glucose due to poor insulin sensitivity, eroded away over decades of high GI food causing relatively large spikes. It makes logical sense considering other receptors can be desensitized in this way. If this is not true, why is it usually the poor eaters or overweight who develop type II diabetes? Is their being overweight or poor eaters perhaps only corollary to their poor health in general? If so, how do we define “health” if not by diet? Activity level? Not to beat a dead horse… Thanks for the replies! I’m learning a lot on your site. Already cut my protein down and that was a big step for me ;)

        • Branr says:

          Quick follow up: If sugar/high GI doesn’t cause insulin resistance or unduly wear the pancreas, are there then any benefits at all to avoiding sugar? I assume that the typically higher volume to calorie ratio and characteristic accompanying fiber content of most low GI whole food (most whole grains, vegetables, legumes) helps out when dieting for satiety reasons, but any pure health reasons?

          • “The sugary drinks link I’m thinking may be simple correlation; sugary
            drinks are high in calories, and thus people who drink them are more
            likely to be overweight, and thus have diabetes.”
            That’s exactly right. Obesity is the great health killer of our society. It’s linked to pretty much every pathology you can think of.

            Sugar is not unhealthy per se, no. Its rapid absorption can have beneficial or adverse effects, depending on what you use it for. However, actual sugar consists of empty calories. So, compared to, say, rice, eating rice will be healthier if the nutrients in the rice benefit your diet. It depends on the overall nutrient profile of your diet and your body.

  7. Sky Stebnicki says:

    Wow, this definitely rocked my world a bit! Do you know if this also holds true when cutting vs maintaining vs bulking? For instance, does it make impede fat burn? Does it accelerate fat build-up when bulking? Thanks again for the awesome research and articles. Please keep them coming! I check every day hoping that your next article is released :)

    • It’s true for cutting and bulking, yes. Most studies are actually on cutting subjects.

      You can subscribe via email (or social media) to get an email notification when a new article is published. See the top of the sidebar on the right. The confirmation email may land in your spam/promotions folder though, so be sure to check that.

  8. TravisRetriever says:

    “What matters is what else is in the food. In sum, a carb is a carb.”
    Just like a horse is a horse of course of course. Sorry, I had to say it. In all seriousness good article. :)

  9. “Pretty much anything you can do for your health pales in comparison to
    being fit and lean. The exceptions are often drugs, e.g. smoking will
    mess you up regardless.”
    And getting a genetic raw deal (e.g. Type I diabetes, sickle cell anemia, to name a few).

    I smell bullshit…I find that website to be hit or miss (hit when Alan Aragon is the author, mostly, haha!). I wish the author could have cited their sources…

  11. David says:

    I don’t have time to research specifics of those studies, but I have a questions:

    Did they do test on people in caloric surplus AND trying to build muscle at the same time? Or were studies only checking muscle-to-fat ratio on people who weren’t bodybuilding and just wanted not to get fat and preserve muscle?

    The idea is to disprove the theory the body builds more fat (and thus less muscle) with high Gi foods in a caloric surplus, than with low GI foods – influence on nutrient partitioning. Of course total fat gain will be the same at equal calories if one isn’t building muscle. And total weight gain will be the same even if one is.

    • To my knowledge, no research has looked at the p-ratio in overfeeding trials in groups of resistance training men consuming different glycemic loads. That said, it is difficult to argue that RT during overfeeding would suddenly change the nutrient partitioning effect of the glycemic index. Why would it?

      • David says:

        Sorry I expressed myself very poorly. In order to prove carb type donesn’t matter in bodybuilding you have to prove it doesn’t have an effect on nutrient partitioning or the so called p-ratio, not just total weight loss/gain. Do you agree?

        How has this been proven?

        “To my knowledge, no research has looked at the p-ratio in overfeeding trials in groups of resistance training men consuming different glycemic loads.”

        If that is the case, shouldn’t that mean that Carb is a carb theory is unproven?

        Also I’m affraid I don’t quite understand the last sentance. I would if it would say the following:

        That said, it is difficult to argue that nutrient partitioning during overfeeding would suddenly change due to the glycemic index. Why would it?

        • The last sentence means that all the current evidence points towards carb type being irrelevant. It would be quite hard to imagine how this would physiologically change in the context of a bulking bodybuilder, since it doesn’t matter in any other context. So the theory isn’t ‘disproven’. Nothing except really strict theories and mathematics can ever disprove anything. However, it’s probability of being accurate is very low.

          • David says:

            Like I said by the fact a sedentairy person isn’t gaining muscle (or at least a measurable amount). Therefore his fat gains can not depend on aynthing else than energy balance. So what do studies on sedentarys actually prove?

            A bodybuilder’s fat vs muscle gain ratio on a bulk on the other hand depens on a million factors, Insulin is a storage hormone, How do we know spinking it over time does not actually contribute to slightly more energy accumulating in fat cells rather than muscle if it hasn’t been directly with experiments in exactly that context?

            Also fast carbs have ben believed to be bad in the bodybuilding culture for decades. Why did this belief evolve if it absolutely no truth to it? Sometimes intuitive traditional knwledge is on to something before science actually proves it.

          • David says:

            Btw. I am not trying to be an a**hole, just playing the devil’s advocate and trying to understand using my own simple logic.

          • There is a vast literature on the psychology of why people believe things that are not true.

            And if you overfeed untrained individuals, they do in fact gain a measurable amount of muscle. Quite a lot actually sometimes.

          • David says:

            I thought this might be the answer, thanks! I just found this hard to believe since I almost get no muscle even if I overfeed when training :( This P-ratio really needs to be researched more imo.

      • David says:

        Now I understand what you meant in the last sentance. Ok why would it?

        Because if one isn’t resistance training he isn’t gaining muscle! (!!)

        So in a caloric surplus he is gaining only fat. But if he is gaining only fat, of course total weight gain is going to be proportional only to total calories consumed (!!) Therefore source of carbs don’t matter !

  12. Colby Coulter says:

    What would be a good way to calculate the amount of carbs to intake while cutting weight and maintaining mass. In other articles you have talked about the disadvantages of cardio, if the diet is sound should no cardio be needed?

  13. J4iez says:

    Hi Menno LOVE YOUR STUFF! You are the man. A few questions:

    would eating clean foods and avoiding unhealthy ones on a very small scale make you have a better hormonal profile(testosterone and other muscle building hormones/processes, insulin resistance) which would also equate to
    having your body in a better environment to build muscle and/or lose

    would you say that bodybuilding aside and assuming all macros and micronutrients are accounted for (I am talking
    about just health/longevity reasons) that choosing foods that are
    considered good like eating hormone free grass-fed, wild caught fish, pastured free range eggs, cooking in the “good oils”, ‘organic’ veggies and avoiding ones that are labeled bad like factory hormoned grain fed meat, factory eggs, farmed fish, cooking in hazardous oils (vegetable/canola oil, soybean etc.)
    ,non organic veggies etc there is any benefit or harm to my health/longevity/disease prevention?? or is it all just media hype
    and a waste of money ? I just want to know if when I am at the grocery store what to do? Or is there literally no evidence suggesting a difference and I should just buy whatever is cheaper or taste better?
    Many would have you believe you are poisoning yourself if you don’t go
    with the natural option (which of course turns out to be more expensive) and sad to say I never know what to believe
    anymore especially with what hear in all this paleo and unprocessed food propaganda. I value your opinion as you actually know how to interpret good
    and bad research =).

    • Those are a lot of questions, ha. A few things:
      – Strictly speaking, no food is healthy or unhealthy. Only a diet is healthy or unhealthy. Though I understand what you mean of course.
      – The more fat food has, the better it is if the animal was fed a diet that it has evolutionarily adapted to. The cost-benefit of grass-fed food is usually small, however.
      – I do believe that eating a diet that provides more nutrients, especially phyto- and zoonutrients, than you strictly need, will in the long term benefit your health (this is difficult to dispute in fact) and your body composition.

      • J4iez says:

        thank you for the reply. ok so grassfed may have benefits but they are rather small. What about being farmed or wild caught fish? will eating unprocessed and less nutrient filled foods make a difference in your health if you are already getting all your nutrients in? I am more just wondering if things are actually worth the money to buy or not. If there is not a significant amount of evidence that it will make much of a difference then why buy them unless you are bill gates? everything organic, grassfed, unprocessed, hormone free are always more expensive.

        are there any foods one should avoid? or is everything fair game as long as you hit your micro/macro’s?

      • Mr Prytania says:

        “The cost-benefit of grass fed .. is usually small” Ugh. It has been shown grass fed beef is leaner and has a more healthy fat / omega composition. “Grass fed” is also an important marker to other qualities that a person might desire in their food such as: no growth hormones, no excessive antibiotics, even certain vitamins are known to be in higher quantities. (See:Smith, G.C. “Dietary supplementation of vitamin E to cattle to improve shelf life and case life of beef for domestic and international markets.” Colorado State University, Fort Collins, Colorado 80523-1171 ) You are what you eat so its best to pay for food only and not food laced with drugs and other trace elements that could hurt us and has hurt us.

  14. eal says:

    if one trains in the am should they not have any carbs post-workout?

    • Why would you need more carbs post-workout in the AM than in the PM?

      • eal says:

        wasnt asking for more was just seeing if there is a reason to or to not have carbs immediately postworkout in the am as I know you say that protein is the only thing needed but was wondering what your protocol with biorhythm is for morning training as for many of us that is our only time to train.

  15. Keith says:

    There are almost exactly the same amount of calories protein carbs and fat in the the baked potatoe with butter my coach says to eat as ther is in a package of Twinkies. So I think I’m switching them …I like Twinkies better.

  16. Justin says:

    “Physically, energy is measured with calories. ‘Energy’ in psychological terms is mainly the result of sympathetic nervous system activity and eating carbs actually decreases this.”

    Can you elaborate on this Menno? I thought our bodies use carbs as a main and more efficient energy source?

    • Justin says:

      Great article by the way. Really enjoy reading and hearing all of your work. So if protein intake is accounted for post workout and carbs aren’t necessary to stimulate or optimize protein synthesis, when would you say are “optimal” times to consume carbohydrates, if any at all?

    • You’re referring to physical energy here. This is something different entirely than what we call ‘mental energy’, which refers to cognitive performance.

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