Data Diva: Sugar

sugarFolks, please join me for a three-part series in which I separate the wheat from the chaff (and myth from fact) on everybody’s favorite topic: sugar. We’ll explore what it is, how it is digested and absorbed, what happens to it in the body, alternative and artificial sweeteners, and the science (or lack thereof) behind sugar’s role in a host of modern ills. If I survive the Sugar Wars, look for more fact-based discussions on wheat & grains, gluten, protein & low-carb diets, calories and body weight, Paleo and more. Fasten your seat belts – it’s going to be a bumpy ride! ~Kaela, a.k.a. the Data Diva

The Sugar Series

Sugar: it’s everywhere. It’s evil, it’s toxic, it’s addictive and destroying our health. To which I say: bullshit.

This same exact scenario played itself out back in the 80’s: the circling of the wagons, the angry mobs with virtual pitchforks and torches, the demands from an outraged public for food products free from the demon seed that was killing us all. Except, back then, fat was evil; fat was toxic; fat was destroying our health. Specifically saturated fat, but in typical American fashion, “good” fats got tossed out with “bad fats” until no one wanted to eat any fat at all. The USDA Dietary Guidelines from 1980, the first year such guidelines were published, are fascinating in that the basic advice hasn’t changed in 35 years: eat a variety of foods; maintain an ideal body weight; avoid too much fat, sugar and sodium; eat complex carbohydrates and fiber; and drink alcohol in moderation. But the devil is in the details as they say. “The major health hazard from eating too much sugar is tooth decay.” Oh, the innocent 80’s. How I miss you.

Back in the day, sugar was relatively easy to spot: it was in candy, of course, and cookies, cakes and ice cream, and we all knew that Froot Loops were neither nutritious nor good for us (hence we wanted ’em even more). But these days, sugar is in everything: crackers and bread, chicken stock and tomato sauce, yogurt and milk and every frozen dinner you can find. But do you know why? Because sugar acts as a preservative and a flavor & texture enhancer for all sorts of processed foods. Much like fat does. So, when we demonized fat in the “heart-healthy” 80’s & 90’s, it was replaced in the convenience foods we demand with sugar (and salt, but that’s a story for another day). Good old innocent nothing-to-see-here-but-tooth-decay sugar.

These days, the wagons are circling around sugar. And the same people who excoriate the demonization of fat in the 80’s and 90’s are perfectly willing to throw sugar under the bus. But it’s not just the white stuff under fire: fruits & fruit juices are under the gun; milk, cheese & yogurt; even vegetables are not safe from our sugar-bashing ways. There are important distinctions between added sugars and the sugars naturally present in fruits & vegetables, but these tend to get lost in the fear-mongering that passes for “debate” on this topic.

evil-sugarWhen did common sense in diet & nutrition go out the window? Since when do we have to ask if fruit is good for us or if it’s healthy to eat four fried eggs and an avocado in one sitting? Maybe it’s a function of our quick & easy access to the internet: we ask because we can. Or maybe it’s the 24-hour newsfotainment cycle that must keep churning, churning, churning away: everyone loves a good ‘breaking’ news story on the latest food that is killing us, right?

So: lest I go all Sam Kinison on y’all the next time I see a toxic-sugar-is-killing-you!!! article, I thought I would try a different approach: data. Science. Verifiable facts and peer-reviewed medical opinion. Because you shouldn’t have to take my word for it: you should be able to judge for yourselves. It doesn’t take a brain surgeon to understand basic nutrition: all it takes is a an open mind, some critical thinking skills, and a little 10th grade biology. Are you ready? Sweet.

What is sugar, anyway? Tricky question that. Most of us think of “sugar” as table or baking sugar: the refined, white crystalline stuff that we add to coffee or use to bake cookies. Crystalline sugar itself comes in many forms: white, brown, raw, powdered. A food scientist may think of “sugar” as the generalized name for sweet, short-chain, soluble carbohydrates, while a biochemist will tell you that “sugars” are mono- or disaccharides composed of carbon, oxygen and hydrogen.

The easy answer is this: all foods stuffs fall into one of three categories – fat, protein or carbohydrate – and sugar is a carbohydrate. Specifically, the term “sugar” by convention refers to simple carbohydrates (image above) monosaccharides like glucose and fructose, or disaccharides like sucrose (table sugar) – while complex carbohydrates (image below), connected strands of many, many saccharides (polysaccharides), are called “starch” or “fiber.” But the reality is they are all made up of the same thing. Amylose, one of the main components of the starch in a Russet potato, is made up of hundreds of linked glucose molecules. Sucrose, the chemical name for common table sugar, is a disaccharide composed of one glucose and one fructose molecule, while lactose, the sugar found in milk, is a disaccharide composed of one glucose and one galactose molecule (which is, itself, simply an isomer of glucose. Confused yet?).

The important thing to remember is this: no matter what carbohydrate you eat – kale, gummy bears, Grandma’s biscuits, apple pie – digestive enzymes will work to break down any carbohydrate that is more than a single molecule. Starches, polysaccharides, table sugar, lactose: anything larger than a monosaccharide will be broken down to a monosaccharide before it is absorbed from the gut. So, in essence, whether you eat stale Cheetos, a bag full of leftover candy corns, or a spinach salad, the only carbohydrates your blood ever sees are glucose, fructose and galactose. And galactose is basically glucose doing a princess wave, so, we’ll focus on glucose & fructose for now.

simple carbohydrate complex carbohydrate
“sugar” oligosaccharide “starch” & “dietary fiber”
1 or 2 saccharides 3 – 10 saccharides >10 saccharides

  • glucose
  • fructose
  • galactose


  • sucrose
  • lactose
minor contribution to US diet

  • onions & alliums
  • sunchokes
  • chicory
  • burdock

  • amylose
  • amylopectin

nonstarch polysaccharides

  • cellulose
  • plant cell wall (dietary fiber)

So, to recap: all sugars are carbohydrates, and all carbohydrates are made up of single (mono) or linked (di or polysaccharides) sugar molecules. This is true whether the sugar in question is spooned into your coffee, crunched in a carrot stick or wolfed down as bread & brie.

Now, before the angry hordes descend on this little blog ‘o mine, take note: I am not saying that a bag of candy corn and a spinach salad are equally nutritious. What I am saying is that after enjoying either of those treats, what will end up in your blood will be much the same thing: glucose or fructose. The total amount, the rate of absorption, and the other components that come along for the ride have as much, if not more, to do with the nutritional quality of any meal than the simplified “grams sugar” that food labels like to trumpet (or whisper).

I am also not saying that everyone should rush right out and start gorging on sugar: there are good reasons for anyone to avoid overindulging in added sugars (tooth decay among them!) and especially good reasons for people with metabolic disorders (diabetes, hypoglycemia). But the best reason to avoid sugar, in my opinion? That you feel better when you do. If so, bravo! Keep on avoiding the white stuff. To find out why your body might react differently to the sugar in a Jolly Rancher than the sugar in a carrot stick, despite the fact that your blood will see the same molecules, join me in the next installment in the Sugar series when I discuss basic carbohydrate metabolism & energy balance, a.k.a. “What happened to all that pasta alla carbonara, anyway?” Until then: science, bitches!

Want more? Read on for Part 2!


  1. Kelli Lytle

    I am a Registered Dietitian and a bench scientist working on my PhD in Nutrition, working on molecular mechanisms that underlie non-alcoholic fatty liver disease. The clarity and truth and a focus on science is a breath of fresh air (I could have cried I swear). Thank you for taking this on, I have thought about doing such a thing and then didn’t have the energy nor time (publish or perish they say *sigh*). Thank you

  2. For a non-scientist like myself, this makes a lot of sense to me – more than the hysterical outbursts I have seen lately. I avoid sugar as much as possible because it does help me feel better than if I over consume, but there is no way I would rule it out of my diet all together. Your post explains very clearly why.

  3. Great article. I suggest you explain the difference of glucose and fructose, and how they differ in their metabolism and absorption by the body, and insulin production. People get confused about cutting sugar from their diets and choosing the right kind of sugars. I avoid processed sugar because they have added chemicals, and raise blood sugar levels faster so I don’t get energy and hunger swings. Cutting sugar also helped me heal inflammation resulted from an injury.

  4. I agree that the end product our blood sees is the same thing. Spot on, that. However, the reason some people (diabetics, weight-watchers, and those who tend to eat out of stress or boredom instead of hunger) need to reduce or avoid consuming sugar is that the amount, and the rate at which this end product reaches the blood depends upon on what form the “sugars” are when you eat them and how much of it you consume in one sitting. The other reason is that unless we are really aware of what’s in our food (all the processed stuff we tend to buy), we are likely to end up consuming more sugar, salt, and fat than is optimal for the normal functioning of our body. Looking forward to future instalments!

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  6. Such a welcome piece among all the hysteria surrounding sugar at the moment. Here in the UK you can’t open a newspaper at the moment without some new “toxic sugar” piece (usually a few pages away from a feature spread on chocolate cake!). Looking forward to the next instalment.

  7. I like your article. You are spot on with your research. But the rate of absorption and energy release is very important. That is why complex carbohydrates are considered better that simple. It is all linked with insulin release, insulin sensitivity and absorption. I covered the similar type of article on my blog “What carbohydrates are you eating”.



  8. BarbaraJean

    Yay, science! Thanks for keeping a steady course. And “…galactose is basically glucose doing a princess wave…” is my favorite quote of the week! Looking forward to future articles.

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  10. Yay! Looking forward to the future installments. I made the decision a long time ago to quit listening to all the media hype when it came to nutrition and to just eat stuff that it as close to the way nature made it as possible. No margarine, no artificial sweeteners, as few chemicals I can’t pronounce as possible. It probably helps that I have good genes, but other than being over-weight (damn my efficient metabolism) I don’t have any real health issues. Great cholesterol levels despite eating lots of eggs (thanks to my chickens and ducks), my bp is picture perfect, and no one ever guesses how old I really am.

    I get tired of trying to explain to people that eating well isn’t hard to do, and that your body knows when it’s getting the real stuff. Keep up the good work!

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  12. A recent brush with breast cancer has had all sorts of advice thrown my way, including avoiding eating sugar. If there’s one thing I’ve learned from the experience, it’s that a “healthy” diet doesn’t prevent cancer. In my case, eating conscientiously has certainly aided my recovery, makes me feel better, and gives me enormous pleasure, but isn’t a cure. If anything, I’m now apt to indulge in a sugary treat more often!

    • So sorry to hear that you are dealing with breast cancer, and I know only too well the avalanche of well-meaning advice that comes in at times like these. My father died of cancer, many years ago, and went down the rabbit hole of macrobiotics, bee pollen & chlorophyll, ayurveda; anything, really, that someone said might help. (It obviously didn’t.) The only advice I have to offer is to do what feels right for you and your body, and that the best scientifically-supported diet recommendations boil down to common sense: I think your road-to-recovery eating plan sounds excellent.

      • Ironically, it was the first person I told about having cancer that warned me of the all of the alternative approaches I was going to be inundated with, and then proceeded to tell me about her own anti-cancer diet… I knew she was just trying to be helpful, and I didn’t have the heart to point out that it was too late for the “anti” part 😉 Thanks for your encouraging words, it means a lot coming from someone whose life has also been touched by this disease.

  13. I am SO EXCITED for future installments, especially related to sugar and fat. I have “metabolic disorder” whatever the hell that means and absolutely love the science behind it all. Thank you!!

    • Human metabolism IS fascinating: elegantly simple and enormously complex all at the same time. And, it is pretty much what I do for a living, although I’m more concerned with the metabolism of drugs than of food. I did, a few years ago, attempt a discussion about fat, and there are a few posts about that here: Unfortunately, I got lost in the morass of diet surrounding cholesterol, saturated fat and heart disease, and the series faltered. Maybe I’ll find the time to pick it up again before the next Dietary Guidelines are issued next year! 🙂

  14. If it were possible, I would climb through my computer screen and give you a great big hug! Thank you for this incredibly well-written and sane piece!! I spent many years teaching introductory physiology, so I can hear my own words echoing in your excellent primer on carbohydrates. I shifted from being a nutrition lecturer to “food-engager” (is that a thing?) a few years back, because I decided that I could better use my skills and passion to do something good in the world by getting kids excited about real food – namely rainbows of fruits and vegetables! I am weary from all the demonizing, misinformation and finger pointing out there, and I couldn’t agree more that good, solid dietary advice hasn’t really changed in decades. I can’t wait for the rest of this series, and I’ve put your blog on my list of favourites!

  15. So nice to read something sane and reasoned on the subject of sugar rather than more fearmongering. Bravo for tackling a subject that makes people really prickly but is mostly fueled by armchair-nutrition and something they read in Cosmo.

  16. Mintychai

    I am going to look for more thing your post under “Data Diva”. We need more science ladies in the world of all-things-food. Thank you! This is a great post and looking forward to next in the series..

  17. I tend to feel better when I reduce my sugar consumption – and from time to time I give it up completely to “recalibrate” my sweet tooth. I can feel like an addict; I want that steady stream of (homemade, of course) sweets all day long. I seem to have it under control right now, but in honor of this series, I just had a big slice of rhubarb kuchen for breakfast. Thanks for your voice of reason!

    • The other day, I had the most FIERCE craving for black licorice. My sweet husband went out at 10 pm to scour the CVS shelves and eventually came home with Good & Plenty. (Which are WAY sweeter than I remember: it’s probably been 20 years since I’ve had any).

      My point being: I rarely crave the sweet stuff, but when I do, it’s a need that must be answered. I downed that box of G&P like food itself was going out of style. But then, craving satisfied, I felt much better, and haven’t thought about licorice since.

      I do think that cravings – for sweets, carbs, protein, red meat, leafy salads, salty things – are cues from your body that it needs something (yes, even sugar). And a craving for candy or cake is not necessarily “bad,” any more than craving a green salad is “good.” I think the real trick is distinguishing an actual “biological” craving, if you will, from the random everyday “I want that” that results from stress, boredom, anxiety, emotional upheaval, etc.

      Of course, that is all my opinion, and may be completely unsubstantiated by fact. I’ll have to look into that. 🙂

  18. Ugh. I just Googled “biological basis of food cravings” and skimmed through 4 articles in a row, all focused on “controlling the impulse,” “conquering” and “not giving in to the craving.” I hate, hate, hate the morality bullshit that surrounds our food discourse. Is it considered “giving in to temptation” if you eat food when you are hungry? GAH. No wonder our relationship to food is so fucked up.

    • EL

      Hi Kaela:

      Thanks for the blog! I think the problem is that we are supposed to crave things when we need them. Unfortunately, some (many?) of us have short-circuited this mechanism. With all the food available and in actuality stuffed at you via ads whether you want it or not, it is sometimes very difficult to tell whether a craving is real or is what might be called a food addiction. That is, if you crave food when you don’t need food, maybe you’re just addicted in some way? I am one person who has a problem shutting this off. Both my father and myself find it easier just not to have food around (efficient metabolisms as well). Otherwise we can convince ourselves to eat non-stop.

      There is some evidence that the bacteria in our gut are involved with appetite and cravings as well and that they play into all this in a big way (this is what I study and tarc mentions this as well, below). So some people do well on a diet, some people don’t need a diet and can follow their cravings and some of us need to be very food aware and don’t need the three a day (which is also a big myth) that other people can happily eat. I find that I prefer to fast (and there is a ton of scientific data on fasting) than to diet, but other people might not like or be able to do that. Certainly each person needs to be sensitive to their own needs and health and not interfere in how another person solves their food issues (or non-issues). This is not a one size fits all and we all need to remember that.

  19. tarc

    A good thing to also remember is that your brain and spinal cord use ONLY glucose to function. Not fats, not amino acids… glucose. Sugar is just fine – in moderation. As a scientist, and a professor of biology (and occasionally nutrition) that regularly teaches nurses and physicians-in-training, the current anti-sugar issue drives me crazy. It’s inane. I’m not ever sure what kinds of jobs these anti-sugar food-Nazis have, but you know, I have to have brain food to do mine. And the idea of ‘processed’ sugar is also full of misinformation. Honey isn’t processed, but it will jack your blood sugar up faster than table sugar. Table sugar? It’s processed with *water* to make it purer… to remove the bits of bugs, and rodent hair, and burned cane leaf (aka carcinogens). The nutritional bonus of molasses vs sugar? Not statistically distinguishable, and, as you mention, rice syrup, agave, and whathaveyou is all the same to your body as table sugar when it hits your blood – we (or out friendly neighborhood gut bacteria) produce all the intraconverting enzymes we need to make glucose and fructose out of anything. In the absence of other medical conditions, it’s simply best to keep your diet balanced and watch your total calories without being insane about it

    • Thanks for the input, tarc. And, oh yes, I have a long rant…er.. “discussion” planned on the relative inanity of thinking that one sweetener is substantially healthier than another. 🙂

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