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).

  • Martos

    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

      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.

  • Tobias

    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.

    • Menno Henselmans

      Good idea. I’ll put it on my to-do list.

  • Just Another Rep

    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

      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.

  • Wouter

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

  • Tristan

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

  • Branr

    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.

    • Menno Henselmans

      ‘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

        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

          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?

          • Menno Henselmans

            “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.

  • Sky Stebnicki

    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 :)

    • Menno Henselmans

      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.

      • Sky Stebnicki

        Excellent, thanks Menno! I’ve subscribed.

  • TravisRetriever

    “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. :)

    • Menno Henselmans

      It’s a reference to the ‘is a calorie a calorie’ debate. ;)

      • TravisRetriever

        Ah. I should have figured. :) My comment was actually a reference to the Mr. Ed Intro (Opening Theme):

        • Menno Henselmans

          One does not simply reference a reference in response to a reference!

  • TravisRetriever

    “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).

    • Menno Henselmans

      Yep, that too.

  • TravisRetriever
    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…

    • Menno Henselmans

      Interesting how a gene can cause a ‘drop’ in body fat…

  • David

    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.

    • Menno Henselmans

      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

        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?

      • David

        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 !

  • Colby Coulter

    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?