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Sugar: Always Evil?

For the sake of clarity, let’s focus this discussion on body composition-related goals (more muscle, less fat), because this topic can get even more murky when considering health, performance, etc.

There are some sugar sources that are obviously ‘bad’ – consuming them often will lead to blood sugar crashes and fat gain. These are the candy bars, sodas, sugary cereals, etc.

Then, there are the ‘acceptable’ sources of sugar that don’t seem to make anyone fat and are often consumed by bodybuilders/physique competitors (factored into carbohydrate macros). For example, blueberries, blackberries, apples, etc.

What is the true differentiator here? Is it just the GI, and thus the total Glycemic Load of the meal? Blueberries provide 11g of sugar per 100g serving (it’s actually the only macronutrient provided per serving in a meaningful amount), but they have a low Glycemic Load, ostensibly due to the fibre content (and what else?) lowering the GI of the fruit. Would a handful of sour candies, coupled with a spoonful of psyllium husk and a glass of water be similarly acceptable? Micronutrients aside, what makes one of these sugar sources a ‘no-go’ for the physique conscious, while the other is readily incorporated into diets?

The topic seems to be somewhat controversial; I’d be interested in hearing about the experiences of others when consuming these foods.

I think that candy bar before working out can be useful.

And no, I don’t think it’s always evil. Like when you are dizzy - you will reach for piece of chocolate or candy or soda… not for bowl of brown rice or something like that…

Everything has it’s purpose.


In that case, do you think that physique competitors often avoid candy bars because of the stigma associated with the food? Or do you disagree with my assumption that physique competitors avoid candy bars?

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I don’t really have much knowledge about bodybuilding honestly.

My guess would be that they do sometimes eat a little bit of candy. Like directly post workout or before workout.

Someone correct me if I’m wrong.

I’m no expert but this is what I go off in terms of sugar. Now that I think about it maybe it’s not the smartest thing to get all my info from one source but meh. It’s worked well enough so far.

I barely get in my macros properly so I’m too busy working on calorie balance and macronutrients to get to thinking about food composition.

When I can manage macros I go with these:

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I’ll go through these resources, thanks for sharing!

The diagram that you posted closely mirrors my thoughts, though, I’m probably disproportionately pedantic about sugar content (given the supposed 5% weighting, provided that sugar content is factored into total calories and macronutrient balance).

Its not about the GI. Fructose in sucrose, and alcohol are much more prone to be turned into triglycerides in the liver than glucose because fructose is 10x more glycosylating than glucose on a mg/dl basis (because it backs up the pylol pathway). This makes even trace amounts of of fructose in the blood harmful, and if the liver can’t process it into glycogen fast enough it has to turn the rest into triglycerides and liver triglycerides are the root “efficient cause” of hepatic insulin resistance and metabolic syndrome. This is one of the reason why, while calorie balance detemines most of body composition, addressing calorie balance is not always a viable strategy for reaching body composition goals, because insulin resistance from too much fructose, omega-6 fatty acids and inflammatory foods can shift energy balance by reducing available energy when it is needed, and because they can block mechanisms that prevent overeating.

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Hmm… I believe that – ‘a calorie is not just a calorie’ – there definitely seems to be a direct correlation between food choices and body composition, even when calorie balance is held constant. I’m intrigued by everything that you said about fructose. I’ve certainly read much about the ‘evils of fructose’ (typically in reference to high-fructose corn syrup). Initially, you specified ‘fructose in sucrose’ – is fructose less harmful when on its own? The rest of your post suggests not, because you discuss:

This makes even trace amounts of of fructose in the blood harmful

Why is it that berries tend not to promote excessive fat gain? Do you believe that athletes who get lean while eating ‘healthful’ amounts of berries (or fruit in general) do so in spite of their fructose consumption? Or is there something inherent about the fructose delivery in fruit that makes it less harmful?

No, the liver can process at least 25 grams of fructose per day. Most fructose is coming from sucrose as sucrose is half glucose and half fructose. 25 grams of fructose a day baseline is probably beneficial because the liver is made to handle about 25 grams of fructose a day (though alcohol consumption interacts similarly so high alcohol intake will reduce fructose that is “good”). Fructose and Alcohol in moderation actually may stabilize blood sugar. Fructose, because it does not need insulin to be used, and alcohol because it occupies certain enzymes which would otherwise cause glycogenolysis (release of glucose from the liver), but above 25 grams of fructose+alcohol and the liver tends to not keep up with turning fructose into liver glycogen, and so it makes fatty liver and insulin resistance. If you exercise hard, the liver has more space to put the fructose and so you can probably add more if you exercise hard. Most estimates are that at about 500 calories an hour 250 will come from carbs, and 1/3 of that can be restored by fructose without a problem, so an hour of hard work can allow for quite a bit more (about 80) grams of fructose and at higher workloads it goes up even more. Alcohol too.

Regarding fruit then, even a high sugar fruit like cherries, grapes, oranges only has about 8-9 grams of fructose for a 5 ounce serving. Strawberries only have about 10 grams of sugar (5 grams of fructose) per 5 ounce serving. Watermelon and Cantaloupe have about 5 per 5 ounces, and bananas only about 10 for five ounces which would mean that you could eat 3 x 4 ounce bananas a day without hitting 25 grams of fructose, and more if you train hard. A 32 ounce soda can have up to 60 grams of fructose.


Just posting to follow the discussion and learn…great stuff guys

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Awesome stuff, thanks for the writeup. That follows – a physique athlete who avoids sugary junk and consumes 2-4 servings of fruit per day would not overload the liver storage, thus avoiding the excessive fat gain/inflammation.

So it seems that it’s primarily a quantity issue – at least where fructose and fructose-containing-compounds are concerned. Thoughts on, for example, candies that are sweetened with pure glucose syrup?

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no, that’s not true. I’m sure there’s a positive correlation, but not a direct one. The term direct is too strong to describe the association, and you’re minimizing total calorie consumption more than you should. You’re actually ignoring way too many variables.

I drink around 5 sodas every single day. I have pop tarts for breakfast, I drink at least half a gallon of whole milk every day, and I usually eat ice cream right before bed. I also eat candy and cookies pretty much every day. I had a milkshake at lunch today, actually, as I do most days. I’m very, very lean.

As far as fruit goes… everything mertdawg said is accurate, from what I can tell. But I don’t believe THAT’S the reason people don’t generally get fat off of eating fruit. I think the actual reason is that there are very few people eat enough fruit for it to be problematic, whereas many, many people eat way too much ‘junk food.’ It’s far more common to see someone eat 500-1000 calories of cookies and soda than it is to see someone eat 500-1000 calories worth of berries, ya know? And you also need to keep in mind that most people who are health-conscious enough to eat a lot of fruit and avoid junk food are likely also making a lot more positive choices for their health and fitness to go along with that.


I agree that the main reason fruit is not a problem is because it is harder to over consume sugar from fruit. I sometimes eat 10-15 ounces of fruit a day, but that’s within my calories and macros. 15 ounces of strawberries only has about 120 calories. 15 ounces of banana only has about 360 and its only 30% fructose.

Fructose is more likely to cause insulin resistance that glucose at lower levels because of the liver’s limitations in turning it into glycogen, and room to put it, but as I said, your ability to dispose of fructose can quadruple if you exercise hard for an hour. Also, in a calorie deficit, you can handle a lot more fructose because liver glycogen stores are staying under-full, but I think its a bad idea to increase fructose and sucrose when in a calorie surplus. Anytime you add some fat you will lose a little insulin sensitivity, but triglycerides, and particularly liver triglycerides are preferentially produced from higher fructose carb sources.

Caloric balance is the most important factor, but if fructose is raising insulin resistance then “calories out” will be decreased on a relative basis because the insulin that should be moving nutrients into muscles end up shutting down lypolysis, so food choices can dramatically effect energy levels, metabilic rate, and also food cravings. which is why the mantra concerning caloric balance, while true, does not provide a strategy for most people to improve body comp. Most people will simply improve their caloric balance if they make better food choices in my opinion. Most people will also be more vigorous and burn more calories if they make better food choices IMO.

Please note that I say this because I, personally have not been successful with mere calories in, calories out formula because I can’t get the nutrition I need on soda and pop tarts, and my metabolism is lower than it was in my 30s, AND because if I make certain food choices, I avoid compulsions to eat too much, and sleep better too, so I don’t eat at night as much.


Pure glucose may as well be white rice. As long as you don’t take in too much, too fast to spike blood sugar, it is not different from glucose polymers (ie starch). White rice and glucose syrup both enter the bloodstream as pure glucose on the same time table.

By the way, type i diabetics used to use juice to raise low blood sugars, but newer research is suggesting that they use glucose syrup like rice syrup, or even certain candies like sweet tarts that are 90%+ glucose because it has been shown to decrease the prevalence in fatty liver disease among type I diabetics who use a lot of juice or sucrose to reverse low blood sugar.

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If you eat inflammatory foods like high Omega-6 oils, or if you are sensitive to dairy, wheat or other foods, then your body WILL release more cortisol when you eat those foods because cortisol has to be released to counter inflammation, cortisol HAS to raise blood sugar, and rising blood sugar HAS to raise insulin levels, and rising insulin levels reduce insulin sensitivity and block growth hormone.

1 night of bad sleep raises cortisol levels enough to increase insulin by 40%. Same effect as inflammatory foods.

Human obesity is linked much more strongly to linoleic acid, fructose and corn, wheat and soy consumption than to caloric availability.


You might like to read about Sohee Lee’s experiment.
I won’t link to her site here, but look for A Snickers a Day Keeps the Cravings Away: A Case for Flexible Dieting.

Also, her article, This is What Flexible Dieting Actually Looks Like.

She’s basically eating wholesome, nutrient-rich foods most of the day, but keeping some calories to fit in a daily candy bar, even during her contest prep. She continued to cut caloric intake as she leaned out.


Where does raw honey fall into this sugar discussion or maple syrup?

Outside of stevia in the raw (rarely). They are the only sugars I consume

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I like to mix raw honey in greek yogurt. It still can trigger cravings, and I think they are both at least 50% fructose, while rice syrup is glucose. Again, fructose is not a problem if you are burning a lot of calories around the time you eat it, or are in a calorie deficit, except that it makes it harder to get essential nutrients, but I would personally not use it for a hypercaloric period because there is less “burnoff” of more harmful energetic substances like fructose and triclygerides and omega-6 in a calorie surplus, and I wouldn’t use it in a calorie deficit because the micronutrient content is low. The time to use it is when you have to work your ass off, but your workload is going to be so high that you won’t be gaining fat. All IMO and I won’t make absolute statements unless the specifics are very tightly defined. There may be a place for fructose even when gaining because fructose can refuel liver glycogen after a workout and keep the liver from robbing glucose from muscles.

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My problem is that I never want to eat just one candy bar, and I don’t crave them when I’m avoiding my trigger foods-particularly ones that make me wake up at night, or hungry or give me allergic symptoms. My theory is that they are raising cortisol, and cortisol has a degree of addictiveness. Well, it does. We know that steroid anti-inflammatories can make people feel really good, raise heart rate, blood sugar and blood pressure. Some people will take a steroid antiinflammatory like prednisone and go walk 10 miles or feel like lifting for 3 hours.

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Hmm… Do you not think that you may be a strict outlier? I’m unaware of others who manage to maintain your level of leanness with such a lenient diet. I suspect that your BMR must be crazy…

In retrospect, I think I agree with your comment about the correlation – ‘direct’ may be too strong a term. We can all agree that there is a positive correlation, however. I wonder about the extent to which this correlation is the result of the sugar in ‘junk food’, as opposed to other factors. For example, I know that many physique athletes will focus on high-volume low-density foods when dieting, in order to maximize satiety while maintaining a deficit. Sugary foods tend not to fall into this category – usually, they offer proportionally less satiation per calorie consumed. This would be an example of another factor. Do sugary foods tend to produce fat gain because of a mechanism associated with the sugar specifically? Or is it perhaps primarily because the sugary foods don’t satiate, and thus people who eat them tend to over-consume? Mertdawg’s comments suggest that a mechanism does exist… But I suspect that the other factors are even more relevant in non-training populations (where calorie totals aren’t considered or controlled).

I agree with your comments about fruit. Very much in-line with the thoughts about high-volume foods above.

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