The Truth About Carbohydrates

This is a guest blog post by Shoshi Domb.


The sun is shining, the snow is melting, and summer is right around the corner. As summer arrives, so does diet season. Since there are so many diets on the market it is sometimes hard to choose a sensible one. Regardless of the diet that you end up following, or your eating habits, one thing that is important to keep in mind is this:

Don’t skimp on carbohydrates.

In the past decade, we are bombarded with ads touting low-carb diets. Before you kiss carbs goodbye, it is important to understand the benefits and drawbacks of carbohydrates consumption (or lack thereof).

What you need to know:

Dietary carbohydrates come in many forms. The 2 main groups are simple carbohydrates and complex carbohydrates. Simple carbohydrates include the sugars, while complex include starch and fiber.

The simplest sugar is glucose and its compound is part of all disaccharides and most polysaccharides. It is an essential energy source for all of our body’s activities.

Starch is the way plants store glucose and can be found in many foods such as rice, wheat, legumes, and potatoes. Since we can digest starch, our bodies break it down to glucose to be used as energy. Humans store glucose as glycogen.

Fiber is the structural part of plants and thus found in many foods: vegetables, fruits, whole grains, and legumes. We cannot digest fiber and therefore it is not a significant source of energy (or calories). However, it has very important health benefits, such as maintaining colon health, relieving constipation, and may help reduce cholesterol levels.

As mentioned, our bodies use glucose for energy. More specifically, muscles are able to store glucose and use it when needed (especially when trying to catch the bus…glucose is your savior!). More importantly, the brain and other nerve cells survive solely on glucose, plus they don’t have reserves like muscles do, so you can imagine what would happen if those supplies are not maintained.

Glycogen is our bodies’ glucose reserve and is present in the liver. Since glycogen is a bulky compound, there is not much room for it and glucose reserves are depleted pretty quickly (within a day; or with exercise, much less).

Even though the other macronutrients (protein and fat) can be broken down to provide glucose, that process is rather inefficient. Protein has important jobs no other compounds can do and should not be interrupted – for example, the immune system cannot function without proteins. Fat, which has unlimited storage in the body, could have been the perfect candidate to provide glucose; however only 5% of its compound can actually be converted to sugar, so it is not a viable option.

It is important to understand is that you should never eliminate a nutrient (specifically carbohydrates) because your body won’t just throw up its hands in defeat and say ”oh well I guess I’m not getting glucose…you win” , but will adapt to these new conditions by breaking down anything it needs to get that glucose.

In this case, it breaks down fat, which may sound like a positive thing to many people. This is the reason we are drawn to carb-free diets, without the knowledge of how this breaking down actually affects us. However, as fat is broken down, fat fragments will start to combine with one another to form ketone bodies.

Ketone bodies are by-products of the breaking down of fatty acids (the portion of fat that can be converted to glucose). They provide energy during starvation when the body isn’t getting any energy from outside sources; however, when too many are produced, they accumulate in the blood and cause ketosis, a condition that disturbs the body’s normal acid-base balance. The effects this can have on your body include acetone-smelling breath, headaches, mental dullness, dizziness and more, mostly due to having very low energy. Prolonged ketosis can cause serious health problems and may, in extreme cases, even lead to death.

Even though carbohydrate consumption is vital, moderation is essential. It is important to mention that any excess carbohydrates will be stored as fat. As there is no limit to how much the body can store, you should be watching the amounts that you are consuming.

The recommended dietary allowance for men, women, and children is 130 g/day (Atkins diet and other low-carb diets allow you to consume only 12-15 g/day). It is also recommended to choose whole grain products and limit sugar intake. To put this into perspective, one slice of whole wheat bread contains about 15g of carbohydrates; 1 medium banana has almost 30g; and 1 cup cooked brown rice contains 45g.

There is no perfect diet. But there are bad diets. Any diet that eliminates or significantly reduces one of the important nutrients cannot be good for your body. Try to eat wholesome, natural food, make sure you include all the nutrients into your diet, don’t forget about the exercise and eliminate stress. Balanced diet, exercise and stress management are three pillars of a happy and healthy life!


Paisley, Judy. “Carbohydrates.” Class Lecture. Ryerson University, Toronto, ON. 19/10/10. Lecture.

Whitney, Ellie, and Sharon Rady Rolfes. Understanding Nutrition. 11. Belmont CA, USA: Thompson Wadsworth, 2008. Print.

Shoshi Domb has an Honors B.A. in Psychology, and is currently studying to become a Registered Dietitian at Ryerson University in Toronto, Canada. She is passionate about health education, especially in regards to children, and also aspires to teach kids the art of healthy cooking.

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  • Erin Westman

    Informative post but could you please do something about the sentence, “Don’t not skimp out on carbohydrates”?

  • Belinda @zomppa

    This is such an informative post, thank you! I just watched a documentary which I don’t even want to name it because it was hard to get through without yelling at it – but it was very anti-carbs, and this helps to put that into context!

  • Larry

    Interesting post, however I think there is a major distinction that needs to be made. Stating that Ketosis can lead to death is extremely misleading and is being confused with Ketoacidosis, which can in fact lead to coma or death. Ketoacidosis does not result from eating a low-carb diet, and is generally diagnosed in patients with extreme diabetes.

    While I agree that people should eat a wholesome diet and eliminating any major macronutrient is unfortunate, the clinical trial evidence suggests that higher protein, low carb diets generally result in more weight loss, decreased triglycerides, increased HDL, and less-atherogenic LDL particles despite being a calorie unrestricted diet! In fact, NEVER IN CLINICAL TRIAL HISTORY has a low-fat low calorie diet resulted in more weight loss than a low-carb, calorie unlimited diet. But don’t take my word for it, here is a source, including the link to every major clinical trial in recent history:

    • Dalai Lina

      What amazes me is how much research shows that a low-carb diet helps heart health profiles. It seams counter-intuitive: eat more beef and lower cholesterol! But the evidence is out there and irrefutable!

      There has to be another part of the body that is effected/compromised by a dense animal protein diet. Save a heart kill a gall bladder? Surely, as with anything, balance is key.

      • Stephanie Smith

        SHORT term evidence is out there. And nothing is irrefutable in “nutritionism”. Margarine was going to save the world for a good 20 or so years, remember?

      • Penny0314

        The entire “heart health” industry–from doctors to nutritionists to the latest diet or diet mod, it really crazy and dangerous. Much of food modified to be “heart healthy” (e.g., Promise Margarine, fat free salad dressings) are nightmares for your body, while butter, actually, is far safer than any margarine. When your cholesterol levels are too low (like 180 that statin drug manufacturers want to make the standard) your immune system collapses and cancer becomes a serious threat. Honestly, the game playing from the “heart health” industry is scary. If you stick to healthy, natural foods, you’ll do fine. What’s promulgated as a heart healthy diet these days is anything but balanced! You’re right, balance is the key!

      • Barbara D Holtzman

        OK, all of you – we’re not talking original Atkins here, which is an “eat all the meat you can” diet – bad for you. Event he Atkins folks have modified it. We are talking low-carb (not no carb), limited fat (not no fat), and the rest of the days calories made up of protein (not all meat). Many vegetables and even fruits don’t count as carbs. Not to mention, the total calorie counts are quite low: 1600 for an average woman, 2000 for an average man. If I get a chance to do the research, I’ll post the refs. IN the meantime, those posted by Larry elsewhere on this thread should give you something to think about.

        • yulaffin

          Atkins was never an eat-all-the-meat-you-want, no carb diet. If you ever bothered to read his books, you would see that he directs one to eat just a moderate amount of protein – enough to satisfy hunger, not enough to stuff yourself. I’ve been following an Atkins eating plan for over five years and am 200lbs lighter than when I started. My diabetes is under good control, my arthritis is a lot less painful and I didn’t eat a ton of meat to get here and do eat a lot more vegetables than meat.

          • BTBC0147

            not true at all he clearly said eat as much as u want and not get fat knowing people would feel full longer and in the end eat less…we get fat because we eat to much food. it will always be about calories
            in vs out, no one has ever been able to prove you can eat more than the
            bodies maintenance level and NOT gain weight…

          • Brian Klein

            Dave Asprey from Bulletproof Exec ate 4000 calories a day with little exercise for 2 years and lost over a hundred pounds. It was a high fat diet. I don’t remember the name of the person, but he also ate a high fat diet in an extremely high calorie range for a month. Gained a couple pounds. Did the same thing using the recommended food pyramid diet and gained much more. These are just a couple examples, and likely won’t work for everyone, but it does work. It’s not so much the calories, it’s the quality of the calories. If you eat the right foods and stay away from the highly processed stuff, you just aren’t going to eat that many calories. Not sure many people will overeat salmon and broccoli. It’s far too easy to over eat potatoes.

          • BTBC0147

            I know of this story,and there is zero proof it is true, also he was and is naturally lean, ..just like the guy who lost weight on the twinkie diet…which proves its cals in vs out…u will feel like crap yes,but no one has ever been able to prove u can eat more then your body needs and not gain weight…think about only 2 people ever made this claim..atkins who admitted he lied..and this guy which has no proof…

          • Ann
          • BTBC0147

            lol he clearly said unlimited…its changed over the years..

    • JS

      Ketoacidosis is actually a a state that can be achieved only in Type 1 Diabetes. In type 2 diabetes there isn’t the problem of a lack of nutrients (ie- fat catabolism leading to ketone body formation) but rather an abundance of glucose in the blood. Just to clarify :)

    • BTBC0147

      KETOSIS another best if you are lucky being in this state u MIGHT burn and extra 100-120 cals a day..providing you do not over eat..

  • Anonymous

    My biggest problem with low carb diets is when they tell you not to eat fruit or veggies! Ridiculous. I am diabetic so I stay away from the simple carbs. And get my intake from fruits and veggies. Or try to anyway.

  • PrimalPalette

    Good article, I enjoyed it. What it doesn’t mention is that excess carb consumption is a major contributor to the American obesity epidemic. Many low-end grains are like candy bars in disguise. It goes both ways. Severely restricting carbs leads to ketosis (the state Atkins folks are going for that I feel is very unhealthy), while over consumption of carbs restricts the body’s natural ability to burn fat. Your body wants to burn fat but it’s usually choking on excess carbs! Somewhere between 75-125g of carbs a day (with a ratio of 75/25 veggies/grains) promotes effortless weight maintenance or loss, depending on if you go toward the lower end. You will not enter ketosis. Your brain will have plenty of glucose. Your body will also be naturally burning fat, and you’ll be getting a ton of nutrients from the organic vegetables. Unfortunately, most people are still mired in the calories in/out illusion, and prefer killing themselves for hours in the gym doing cardio. You don’t have to. 20 minutes of exercise 3-4 a week and a smart diet is all it takes!

  • Mr. Bill

    What a wonderfully informative post to read while eating my homemade wheat bread with peanut butter. Thanks!

  • Jones

    This is an interesting article, but the lack of scientific basis for some of its claims is disturbing. It is not surprising given the dogma of the established nutrition community, but I would implore the author to do a bit more research or at least avoid making such claims as “Any diet that eliminates or significantly reduces one of the important nutrients cannot be good for your body.” Where does this notion of “cannot” come from? Does it come from peer-reviewed and duplicated studies? I suggest that that is not the case. As Larry said, the author is obviously confusing ketosis with ketoacidosis. Try reading Gary Taubes’ Good Calories, Bad Calories, and if that’s too much for you, Why We Get Fat.

    • BTBC0147

      we get fat because we eat to much food. it will always be about calories in vs out, no one has ever been able to prove you can eat more than the bodies maintenance level and NOT gain weight…

      • Dean

        Wrong. Jones is right. Here’s some thought for food: Read “The Calorie Myth” by Jonathan Bailor. Your statement is not only completely incorrect, but it also completely ignores weight gain that is due to Thyroid, Hormone, and other Metabolic issues. The saying “Calories in, calories out” is a cute saying, but is completely false. Example: using your logic, eating a chocolate donut, containing 195 calories, would be a healthier choice than eating an Avocado, with 235 calories. It’s NOT about the Quantity of calories, it’s about the QUALITY. Please educate yourself, and stop spreading 50-year-old Dogma that has been proven inaccurate, time and time again, using legitimate science.

        • BTBC0147

          of course an apple will do better and make you feel better then candy but the fact remains..and weight gain due to thyroid etc shows you need more study,most obese people have very normal functioning thyroids..I have hypothyroidism so I have to really watch my cals..we all agree 3500 cals(rounded up) make a lb of fat but negative 3500 does not lose a lb? lol every top expert and scientist clearly agrees it is all about a calorie deficit end of story..biggest proof..gastric by pass…lap band…the biggest loser..the ice cream diet..the guy who lost 35 lbs lbs eating twinkies..(of course that is not good and I am sure he felt like crap but fact remains) again I say and I said to MR BAILOR WITH NO REPLY NO ONE HAS EVER BEEN ABLE TO PROVE YOU CAN EAT MORE FOOD THEN YOUR BODY REQUIRES AND NOT GAIN WEIGHT…

  • csg

    I have to somewhat disagree here. Many people suffering from Crohns, Colitis, IBS, and other gastro disorders as well as autism and developmental disorders have found huge success with the Specific Carbohydrate Diet. This diet eliminates all grains including glutens, corn and rice. It also eliminates all sugars and sweetners except honey. You basically do not eat any processed food and concentrate on meats, veggies and fruit. You are not completely eliminating carbs since you are eating carbs from veg and fruit. I have not heard of one person doing this diet that died from it. As a matter of fact, many have found increased health and vitality and no longer need meds and/or surgery. In terms of developmental disorders, unusual behaviors can be more controlled or eliminated such as stimming. It is a very, very difficult diet to follow and it is hard to go out to dinner and such with friends. However, I just wanted to add that going “no carb” in this way can be very helpful.

    • Lenny

      This post is geared toward the general population. I don’t think she would disagree that in specific disease states restricting carbohydrate intake could be beneficial.

  • Maryp

    One misconception – Atkins only restricts carbs to 12-15 (or 20) in the first two weeks. You gradually begin adding more carbs until you get to the point where you stop losing weight and decrease them to find that point at which you can continue losing weight.

  • Amy_in_StL

    I have no idea if going low-carb is bad for you. I did lose weight twice that way. Once was on Atkins and the other time was on a medically supervised liquid diet. Both times I experienced what I called “Constant Blonde Syndrome”. I felt like my brain cells were having a hard time making the needed connections for decision making at work. I indeed felt mentall dullness as the article suggests. Most engineers and scientists I know have described the same feelings and found it frightening to not be able to figure things out quite as quickly. Honestly, I’ve always assumed that people who didn’t feel this when on a low carb diet didn’t have a highly functioning brain anyway.

    • JS

      Well to me just that fact that you said you “lost weight twice that way” should send up red flags. Shouldn’t any weight loss plan be sustainable? I mean really that’s the goal right… Also, the symptoms you experienced are extremely common with low carb eating. If you are involved with any sports or physical activity you would also see a dramatic decrease in your sports performance. Low carb is bad news and as a dietitian wouldn’t recommend it to anyone..

    • Lisa

      The brain fog likely came from a lack of overall nutrition, particularly in the case of the liquid diet. Not to say that going low carb is or isn’t wrong, but I don’t think carbs were to blame there.

  • From EKleiman’s FB

    “Atkins and other low-carb diets” don’t actually recommend that low of a carbohydrate intake for a sustained period of time (i.e. no more than a week, but typically a few days).

  • OriginalBuddha

    This post is full of fail and I don’t even have time to debunk all this garbage. 130g of carbs a day is 520 calories. For a dietitian someone doesn’t understand nutritional macros.

  • Dan

    I really enjoyed this article. This is a really important issue, and one that many people are clearly divided on, for many different reasons. I have friends who have had terrible reactions to low-carb diets. Given the conflicting nature of studies on both sides of the issue (as exists in the vast majority of food and health research in general), I think the main point of this article is a good one! It’s about having a complete diet, rather than one which stresses your body, potentially causing negative side effects.

  • Jmercantini

    May I suggest that the author check out the Metabolism Society?
    and find out the truth.

  • Jmercantini

    May I suggest that the author check out the Metabolism Society
    and find out the truth about carbs.

  • FrugalArugula

    Anyone that who thinks that a low carb diet is a carb-free diet is a freakin’ moron.

    Atkins suggests 20g per day and it’s the lowest and after the 2 week period, it’s South Beach. South Beach doesn’t count carbs but it’s probably around 40g.

    With the diets (as in day-to-day consumption) that people are living on these days, pulling people back to eating green leafy veggies, etc., as opposed to the joke of a bread “whole wheat” or “whole grain” is these days is probably pretty necessary.

    But to write this up as if lower carb diets don’t suggest that you eat A TON of veggies is absolutely ridiculous.

    Personally I don’t see anything wrong with any of these diets on the sustaining level. And to be honest, I’m shocked at fooducate’s stance on this, what with all the sugar hating that goes on here.

  • Janet Nezon

    Great job summarizing the basics of carbohydrate metabolism! I’d love to use it for my Anatomy & Physiology students! When it comes to taking the science and putting it into practice, the basic principles of a healthy diet haven’t changed much since I did my Nutrition degree back in the 80′s (at UofT -under David Jenkins). I remember thinking then: “whole foods, balance, variety, moderation -and get moving!” Now as an educator helping families and kids to eat well, I still hang my hat on those same principles! The research news gets people running in different directions on a very micro level, but I believe that for most of us, the big picture still looks the same -bravo Shoshi!

  • Lisa

    I think what it comes down to is personal preference and body tolerance.

    I’ve never been overweight and kept my BMI and body fat low. I keep a balance between good carbs (veg, whole grains and a little fruit), fat and protein. I’ve stayed healthy and had cardiologists tell me my heart is in great shape (I see one regularly to monitor my heart since I’ve had congenital defects fixed). It makes no sense to cut things out of their diet without need, and I agree: whenever I hear of people cutting out whole food groups on a whim, or severely limiting them, I just shake my head.

    Yes, carbs in excess can put weight on you. But so can anything else if not balanced properly. If you’re eating moderate amounts of good carbs, eating well overall and working out, it shouldn’t be a problem.

  • Lisa

    I keep coming back to this post to read comments and RT’s. Skimming the article again, I noticed the recommended number of grams at the end: 130 g. As far as I’m concerned, and from what I’ve heard Gary Taubes say, that’s not a bad minimum. According to the Primal Blueprint, that falls within maintainance range. only when you go above 150g/day and into the 200 and 300′s are you heading in the wrong direction. If you’re not looking to LOSE weight, and not all of us have to!, then saying that she got it ass-backward with this post is, well, ass-backward.

  • LowCarbIT

    The real truth about Carbs and the Food Pyramid:

  • Brian

    Plenty of good carbohydrates can come from vegetables and (limited) fruits instead of bread, or more specifically, grains. So where you get your carbohydrates would be a more productive discussion than not skimping on carbohydrates. I’ve cut out grain almost entirely, almost no sugar, and no processed foods, and I’ve felt better than any time in my life…. lost 25 lbs (I’m 5’11″ and went from 215 to 190,)  dropped 100 pts on my cholesterol levels, and brought triglycerides to normal levels as well. I used to eat a ton of bread, chips, crackers, beer, etc. Always low fat, yet I could never lose fat, and my disease markers were high.

    See this article: (the first of a 3 part series) explaining carbohydrates, and which ones are good and which ones are bad.) There are many other good sources of information included in the comment thread.

  • full liquid diet

    Despite the fact that the patient could not be able to eat heavy and sumptuous foods, he and or she can still be able to obtain the right level, amount, and type of nutrients and vitamins within a specific time-frame. Through it, the patient would certainly not suffer from malnutrition excluding the fact that they will be limited upon the type and amount of foods that they will consume.

  • Xenia

    When you say that carbohydrate consumption is “vital”, on what exactly do you base this claim, seeing that the carbs are the ONLY non-essential macronutrient – which means there is no minimum daily required quantity to keep us alive?

    In other words, you could stop eating carbs right now and live forever. I am not saying that we should do that – after all, some vegetables are healthy and they are mainly carbs. But we do not need them because they are carbs, we need them because they contain lots of healing vitamins and minerals.

    Our body can make carbs out of protein or fat which means our body is USED to functioning without carbs. That is why carbs are completely non-essential for us. But we cannot say the same for proteins and fats.

  • Dave Sill

    Sorry, this article is just bad.

  • Sebastián

    Carbohydrate consumption is not vital. The essential macronutrients are primarily protein and fat. Protein being necessary for the production of almost all bodily tissue (cell walls, DNA, muscle and connective tissue, etc.) and fat mostly for normal hormone function.

    I suggest not trusting in anything blindly, rather using some common sense and solid scientific basis (which can vary from study to study) and reading with sound judgement.

    Great hub for low-carb studies =

    • Fooducate

      You are simply wrong. Please reread the blog post.

      • Brian Klein

        How do you explain people put on extreme ketogenic diets as a treatment for seizures. They suddenly live seizure free, and eat almost no carbohydrates. And don’t die from it. It’s a specific reason to not eat carbs, but that should be pretty good proof that they are not essential. I’m not saying people should eliminate carbs. I often promote carbs as a healthy source of food, as long as they get them from the correct sources. But people can live well without carbs. See:

        • Fooducate

          It’s not a no-carb diet. Quoting from the link you provided Brian:
          The typical ketogenic diet, called the “long-chain triglyceride diet,” provides 3 to 4 grams of fat for every 1 gram of carbohydrate and protein.

          • Ann

            See: This is the Institute of Medicine’s 2005 macronutrient report. See p. 275: “The lower limit of dietary carbohydrate compatible with life is apparently zero, provided that adequate amounts of protein and fat are consumed. However, the amount of dietary carbohydrate that provides for *optimal* health is unknown.” [emphasis mine]. Dietary carbohydrate is not an essential nutrient; for some people it may be a part of “optimal” health, for others not. This question is unanswered at this time.

  • Ted

    This is all so confusing. I’m just going to relax and watch TV while I eat some ice cream.

  • jonathanwr

    Ketosis is not a “dangerous” state to be in – that would be ketoacidosis. The human body does not require significant carbohydrate amounts in order to survive. The body produces its own glucose – this can be achieved regardless of whether the calorie is a fat, protein or carbohydrate.

    Carbohydrates in the diet are largely responsible for that “dull”, apathetic feeling. Blood sugar is too high and insulin is trying to regulate it. Carbohydrates are the only energy source that boosts serotonin. High serotonin levels (induced either by food or from prescription drugs like SSRIs) act as a tranquilizer. However, this prolonged elevation can lead to sedation and helplessness, reasons people quit taking the drugs (described as amotivational syndrome).

    Carbs aren’t “evil”, but they are HARDLY essential!