Paleo Diet: Is Sugar Really The Devil?


Sugar! Image Courtesy of Wikipedia

It’s a frequently repeated idea around the world today, that sugar could quite possibly be the sweet, white disguise that the devil uses to enslave us on the earth. Sugar is commonly implicated as the major contributor to the development of insulin resistance, diabetes, heart disease, and cancer. But, is this reputation actually deserved?

If there is one thing I have learned since I began this whole low-carb slash ancestral health journey, it’s that there is almost no piece of information, from any source that is sacred, trust worthy, or absolutely true. What if sugar actually wasn’t as bad as everyone says it is?

Just last week on February 22nd 2012, Stephan Guyenet of Whole Health Source, posted an article entitled simply “Is Sugar Fattening”, that addresses this sensitive question at length. The article is pretty lengthy, so I’ll include a few excerpts and the conclusions here, but you should really take the time to read it for yourself. Stephan includes a few charts and graphs that I won’t

show you here.

Primate and Human Evolutionary History with Sugar

The earliest primates living more than 60 million years ago likely subsisted on fruit, leaves and insects, as most primates do today (Richard Klein. The Human Career. 2009).  Chimpanzees and bonobos, our closest living primate relatives (~6 million years of divergence), are mostly frugivorous, meaning they’re fruit eaters that obtain much of their energy from fruit sugars.  For what it’s worth (perhaps not much), these primates are both extremely lean in the wild.  It’s likely that our last common ancestor with them relied heavily on fruit.

Humans probably began to diverge from our ancestral primate dietary patterns around 2.6 million years ago when we developed stone tools.  Archaeologists think this is when pre-humans began hunting/scavenging animal foods more frequently and relying more on animal sources of nutrition (Richard Klein. The Human Career. 2009).  Some time over the ensuing two million years or so, we began using fire regularly and eating more starch foods, also presumably at the expense of leaves, fruit and insects.

However, our ancestors never abandoned their fruit-eating ways, and modern hunter-gatherers continue to eat fruit and honey when available.  In equatorial and many temperate regions, fruit and honey together are a major source of calories during much of the year, and thus the diet contains a significant amount of sugar.  For example, the Hadza hunter-gatherers of Tanzania rely heavily on fruit and honey (1).  !Kung hunter-gatherers of the Kalahari desert also eat a substantial amount of fruit and sometimes honey (Richard Lee. The !Kung San. 1985).  Both groups are characteristically lean.  These cultures presumably eat in a way that resembles the diet of our own human ancestors.

There are also many examples of non-industrial horticultural and agricultural groups that eat fruit regularly.  For example, according to the work of Dr. Staffan Lindeberg, residents of the Melanesian island of Kitavans obtain 50 g of carbohydrate per day from fruit, most of which would presumably be sugar (2, 3).  This is about half the amount of sugar Americans eat today (discussed below).  Dr. Lindeberg’s research showed that Kitavans are quite lean, and have an undetectable incidence of heart attacks, stroke and diabetes.  Their fasting insulin levels are low by Western standards.

It is difficult to escape the conclusion that our ancestors have been consuming sugar, in the form of whole fruit, continuously for the last 60 million years.”

Some Paleo people try to deny the idea that Paleolithic people ate a lot of fruit, but according to the data, a substantial amount was almost certainly eaten by hunter-gatherer groups, and generally still is today.

“The studies that compared glucose to fructose are surprisingly consistent with one another in rodents, dogs, and (discussed below) humans.  When diets high in glucose are compared head-to-head with diets high in fructose (and sometimes sucrose), the fructose diet increases circulating insulin, causes insulin resistance in the liver, but total body fatness remains similar between the glucose and fructose groups in almost every case (21, 22, 23, 24, 25, 26, 27, 28).  This is also true if the sugars are administered side-by-side in drinking water (28a).  There is no difference in the effects of glucose, fructose or sucrose on total body fatness in animal models, suggesting that sugar probably does not have an inherently fattening effect that is independent of its calorie content and flavor.”

“As a whole, the animal research suggests that sugar and fructose are probably not inherently fattening, but that they can be fattening when they are used to increase the palatability, reward value and energy density of foods and beverages.”

“Now let’s examine studies that compared glucose to fructose feeding in humans, which would identify any unique fattening and metabolic effects of fructose, and by inference, sugar.  Perhaps the most interesting study was conducted by Dr. Peter J. Havel’s group in 2009 (34).  They had volunteers obtain 25 percent of their energy needs from beverages sweetened with either glucose or fructose, for 10 weeks, without controlling total calorie intake.  They used precise measures of body composition and distribution before and after the intervention.

In perfect agreement with the animal studies in rodents and dogs, total body fatness increased the same amount in both groups provided with refined glucose- or fructose- sweetened beverages.  Also reminiscent of the animal studies, the fructose group saw a rapid increase in visceral fat specifically, an increase in fasting insulin and insulin resistance, and an increase in blood pressure.  Thus although the refined fructose strongly promoted elements of the metabolic syndrome, it did not have any special ability to increase total fat mass beyond what occurred simply by adding a sweetened beverage to the diet.  It’s worth noting that these volunteers were receiving very large quantities of refined fructose, which it would be difficult to obtain via a normal diet.

This result is consistent with a number of other fructose feeding studies in humans, reviewed in a brand new paper in the Annals of Internal Medicine (35).  The investigators reviewed 41 human fructose feeding trials.  They concluded that fructose is not fattening when substituted for other carbohydrate in the diet, but it can be fattening if consumed in addition to the typical diet.  This fattening effect is equivalent to what one would expect based on the increase in calorie consumption in these trials. “

Alright, here come the conclusions…, is sugar really the devil in disguise?


Here are the take-home points from this post:

1. Sugar, including fructose, is not inherently fattening relative to other calorie sources, and unrefined sugar is compatible with fat loss in the context of simple whole food diets.

2. Sugar can be fattening in certain contexts, specifically if it is added to foods and beverages to increase their palatability, reward value and energy density.

3. Sugar-sweetened beverages are probably one of the most fattening elements of the modern diet.

4. Fruit is not fattening, and it may actually be slimming.

5. In excess, refined sugar can cause body fat to redistribute from the subcutaneous depot (under the skin, where you want it) to the visceral depots and the liver (where you don’t want it). It can also cause insulin resistance in the liver and increase blood pressure, all components of the ‘metabolic syndrome’.  This is caused specifically by the fructose portion of the sugar.

Here are the implications:

1. Avoiding sugar-sweetened foods, and particularly sugar-sweetened beverages (soda, punch, sweetened coffee, cocktails, maybe fruit juice as well?) can prevent and to some extent reverse fat gain and metabolic dysfunction.

2. I see no reason to believe that refined and unrefined sugars, used in the same context (e.g. muffins baked with white vs. brown sugar), would have different effects on body fatness.  However, unrefined sugars may be less harmful to other aspects of health, because they contain other substances that may be protective.  Mark Sisson discussed this idea in a recent post on honey (38).

3. Eating fruit does not contribute to fat gain in most people, but instead probably favors leanness.  Fruit is a whole food with a low energy density and a moderate palatability and reward value.”

So it looks to me like sugar can certainly make people fat, if we eat too much of it……but that’s true for ANY food. No matter what it is, if you eat too much, you will gain weight. I think that’s one point that many people in the Paleo or low-carb world seem to be in denial about. If you eat too much…..of anything…you will gain weight. Calories do count folks, and eating too much steak will put just as much weight on, as eating too much sugar. Is sugar the devil? No, but it CAN be.

Personally, I use some sugar in my coffee, and I eat quite a bit of fruit. According to Stephan, that should be perfectly fine, especially since I don’t have any major metabolic derangements to speak of. Is the same approach good for everyone? Not necessarily, no. Someone with Diabetes might require a different approach, however on the whole, I believe that fruit and small amounts of refined sugar can fit in just fine with a healthy Paleo/Primal lifestyle.

What do YOU think about this article? Let me know!


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Barry Cripps is a Paleo-based, Certified Nutrition and Wellness Consultant, who operates out of Bowling Green, Kentucky.

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2 Responses to Paleo Diet: Is Sugar Really The Devil?

  1. Matt LaScala February 28, 2012 at 12:47 pm

    If you’re coming from an American-style diet of Danishes and corn syrup-infused sausages, yes, fruit is slimming because you’re replacing heavy, fiberless fructose sources (candy) with fibrous, relatively light bags of fructose (actual fruit).

    But our big, sweet fruit has been cultivated and selectively bred for that size and sweetness over many generations. You can’t just plant a peach pit and get a peach tree that will produce the kind of peaches you want: you have to graft from an existing peach tree that already does. Most natural fruits besides berries are greasy and incredibly sour, and not in the good way; plant an appleseed and see what you get.

    Point being, if you’re coming from a super healthy variant of the paleo diet, with pastured meats and organic vegetables and good sleep practices and ideally not a ton of chemicals all over you from environmental sources, fruit IS fattening at the margins. Eat dates or mangos or bananas or even apples or pears in the quantities you’ll want to, because they’re sugary delicious, and you likely will not maintain a totally ripped Men’s Health style six-pack. Fitness models do not eat a ton of fruit.

    Since our bigger concern is health, the conflict of eating delicious fruit versus being mad jacked (a bitter conflict for most of my life as a vain athlete, to be sure) is a tiny one, though even fruit sugar, I find, will screw with my progress towards my athletic performance goals, just like a day eating candy will make sure I’m weak and slow for a night workout (N=1 here, of course).

    But this article suggests that if we stay away from the lectins and the saponins and the phytates and the insectisides, we can go weapons-free on a little sugar. I don’t think that’s true for civilized people. We have too much access to an endless supply–access that opportunistic honey- and fruit- eating hunter-gatherers lack–of a drug that’s proven addictive. If you have any guilt or shame around the issue, what starts with sensible consumption will probably end with a binge, and you probably won’t stick to gluten-free gummy bears.

    I say stay off the sauce. Make it two weeks and you’ll feel amazing.

  2. HeatherT February 28, 2012 at 3:34 pm

    Back when I was a kid, back when everyone was a lot thinner, it was just a given that there would be an apple or an orange in our lunch. And jelly on the sandwich. My Mom was even more extreme: there were always bowls of candy out. Also bowls of fruit and nuts. We could snack on any of these if we got hungry.

    Oddly enough, we usually chose the fruit or nuts. We didn’t like the candy much and it usually went stale. We did pig out on candy on Halloween and Christmas … a tradition I guess. But we ate the fruit quite a bit, and we were thin. I don’t think it is possible to really “pig out” on fruit. It fills you up. Even when I’m really, really hungry, I can’t eat more than one apple. Eating the equivalent of say, one soft drink, in apples, would be really difficult. You could do it though, if the apples were juiced, or dried.

    We didn’t pig out on the nuts, because they were still in the shell. We had to crack each nut before eating it. After awhile we got full. Or tired of cracking nuts. But we didn’t eat a huge pile of them in any case.

    So while you are talking about “paleo” foods, maybe it’s time we talked about “paleo cuisine”. I.e.: take into account the format of the food, how it is prepared, and how it is mixed with other foods. Part of the issue of “other foods” also is the effect they have on appetite. The fact a kid craves sugar so badly that she’ll drink a whole Big Gulp speaks to some kind of imbalance in the foods she gets.