Is Sugar Bad For You?

If sugar is bad and “toxic,” then what should you think about fruit?

It’s the hypothetical question that rarely gets answered — or is even considered — for anyone considering a no-sugar diet

Before you buy in to the easy-to-sell idea that sugar is the root of all evil, you might want to consider the familiarity of the script. Yesterday, fats were going to kill you. Today, fats are on the path to redemption — some are not as unhealthy as we thought, while others have hidden health benefits.

But in the minds of many, an “obvious” enemy has emerged: carbs and, more specifically, sugar

And yet, the question remains, “is sugar bad for you” in any dose, or — like almost anything else — is the issue more about how much you’re eating and where it’s coming from? When you dig deeper into the science, you’ll find that going “sugar-free” might be unnecessary if you want to lose fat, live longer, and feel great every day.

Not All Sugars Are Created Equal

Sugar is far more than just the white stuff you spoon into your coffee. (That’s sucrose.)

In biochemistry, a sugar is either a monosaccharide or a disaccharide (“saccharides” being another name for “carbohydrates”).

  • A monosaccharide is a simple sugar.
  • A disaccharide is a sugar composed of two simple sugars.
  • An oligosaccharide is composed of two to ten simple sugars.
  • A polysaccharide is composed of two or more simple sugars (300 to 1,000 glucose molecules in starch).

In short, all carbohydrates are composed of single sugars. If we go back to the example of sucrose, or table sugar, that’s actually a disaccharide of the simple sugars glucose and fructose.

Meanwhile, starch, dietary fiber, and cellulose are polysaccharides. That’s an important distinction for those of you keeping score at home: fiber — something most people know as good — is also a form of sugar.

Of those three, we can only digest starch, which is composed of glucose. Starch is also what you’ve probably heard call “complex carbs” or “slow carbs” — slow because the body needs time to break them down into single sugars (notably glucose, the “blood sugar”).

So the idea of true non-sugar diet means kicking out a lot of foods that are perfectly healthy. Sure, you can live without ingesting sugars, or even carbs … but only because your body can synthesize the glucose its needs out of fatty acids and amino acids.

This happens because your body needs sugar. Glucose is needed as fuel for important functions, like your nervous system and your brain. (Yes, your brain doesn’t only function on glucose, but it does need glucose; and glucose also helps cells interact.)

Maybe more importantly: there are many perfectly healthy foods that contain sugar (see below). Any no-sugar diet that would insist removing all of the following foods can’t be foolproof, right? And that’s the point: any diet that veers towards extremes oftentimes is misguided, and that includes the catch-all “don’t eat any sugar.”

Answer the question: Is sugar bad for you?

Like most things in life, the poison is in the dose.

As we’ve seen, your body actually needs sugars, to the point that it’ll manufacture some even if you avoid all carbohydrates.

But consuming too much sugar leads to type-II diabetes and obesity (though overeating will make you fat even if you aren’t consuming many carbs). Too much sugar also results in an increase in advanced glycation end products, and so in skin damage and a greater risk of cancer and cardiovascular disease.

That’s why added sugar can be dangerous: not because it’s “as addictive as cocaine” (it can be addictive, but not nearly as much as cocaine or as the act of eating itself). The real danger with sugar is not that it’s inherently fattening. A gram of sugar is still just 4 calories. And 4 calories will not make you fat. However, you can eat a lot of sugar and not feel full. So you eat some sugar…and then some more…and then some more…and next thing you know a box of cookies are gone — and you’re still feeling hungry.

Added sugars are all too easy to overconsume. That’s true of every added sugar, no matter how healthy-sounding it may be. “Cane sugar,” for example, despite being natural, isn’t a lot healthier than other sources of sucrose. Conversely, the much-vilified high-fructose corn syrup (55% fructose, 45% glucose, usually) isn’t a lot worse than sucrose (50% fructose, 50% glucose).

What are especially treacherous are sugars in liquid form. You can drink and drink and drink mass quantities of them—enough calories to account for a five-course meal—and yet still feel hungry. Perhaps it’s unsurprising, then, that soft drinks are linked to the current obesity epidemic. Sodas and colas are by far the main source of added sugar in the average American’s diet, accounting for 34.4% of the added sugar consumed by U.S. adults and children.

In that respect, fruit juices aren’t any healthier. In fact, they can be even worse. Why? Because the sugar in fruit juice is fructose, which can stress the liver (only the liver can metabolise fructose in any large amounts). Current evidence also points to the consumption of fructose causing greater weight gains than glucose.

But the same isn’t true for the sugars you’ll find in vegetables and fruits. In fact we need to be clear that, to this day:

There is no evidence that eating fruit, even in high amounts, will harm your health.

Unlike fruit juices, whole fruits are filling. Apples, though solid, are 10% sugar … and 85% water; that alone makes them very hard to overeat. In addition, recent studies show that whole fruits may help regulate blood sugar.

There’s one “sugary” drink that doesn’t pose the same threat: milk. While milk contains sugar (lactose, a disaccharide of glucose and galactose), it has far less less than fruit juice, since milk also contains protein and fat. Back in the day when fats were the enemy, low-fat milk was considered healthier than whole milk, the same isn’t true today. Now that fats have been (partially) redeemed, whole milk is back in fashion — and backed by lots of evidence.

So how much added sugar can I eat per day?

Here’s something we can all celebrate: you don’t need to feel guilty each time you eat added sugar. But you should stay aware of your consumption and do your best not to exceed these limits:

  • 100 calories/day if you’re a woman (about six teaspoons, or 25 g);
  • 150 calories/day if you’re a man (about nine teaspoons, or 36 g)

What does that mean? You’re looking at 1 full-sized Snickers or about 7-8 Oreo cookies. But note that we’re not saying you should add a Snickers or Oreos to your daily eating plan. The example here simply illustrates the total quantity you’d want to cap your day at. But keep in mind: Added sugar winds up in a lot of unexpected places, like soup and pizza.

While the average consumption of sugar in the United States may be decreasing (it was up around 400 kcal/day in 1999–2000, dropping down to about 300 kcal/day in 2007–2009), it’s still way too high. And of course, it’s an average, and averages lie. Some people consume a lot less, and others … a lot more.

But let’s say you don’t like one-size-fits-all numbers. You don’t want to carry around a set of measuring spoons all day, or worry about how many grams of sugar you consumed. If that’s the case, here’s an even easier way to keep your sugar consumption in check. It’s based on the model of the old school Food Guide Pyramid, which was released in 1992 and replaced in 2005 by MyPyramid—before that was eventually replaced by whatever this thing is that the government is using nowadays.

Two pyramids compare healthy vs. unhealthy intakes of added sugar. Healthy has more natural sugars than added, while the reverse is true for unhealthy.

The base of a healthy sugar pyramid is made of vegetables and fruits: Not only are they filling, they also provide you with fiber, vitamins, minerals and phytochemicals (biologically active compounds found in plants, some of which are beneficial to our health), in addition to the sugar. Whole milk can also go there. The little sugar naturally occurring in bread doesn’t count as added sugar, either—but the sugar that’s often added during manufacturing in the U.S. does.

As for fruit juices, honey and maple syrup, they all count as added sugar, as does high-fructose corn syrup.

So that’s it. Just keep this pyramid in mind. If the base of your personal sugar pyramid is wide, then sprinkling a little added sugar at the top won’t make it collapse. It’s only when most of the sugar in your diet comes from soft drinks, sweets, cookies, breakfast cereals and the like, that your pyramid is likely to topple, and your health along with it.


Do Carbs Actually Make You Fat?

Winning the War on Hunger: Practical Solutions to Overeating

Healthy Fat: Which Foods Should You Really Be Eating?

Kamal Patel is director of, an education company he cofounded in 2011. Since that time,’s growing team of researchers has reviewed thousands of studies on supplementation and nutrition. Today, over a million visitors each month rely on to separate marketing hyperbole from scientific evidence.


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