How sugar is making us sick (and 6 reasons to avoid it)

From the desk of
Robb Wolf
ScienceHow sugar is making us sick (and 6 reasons to avoid it)

Obesity, diabetes, leaky gut, heart disease, cancer, and dementia. These health problems don’t have just one cause. They’re multifactorial. But if you could pick one thing to eliminate from the modern diet—in order to dramatically reduce the risk for developing these conditions—you could make a strong case for eliminating refined sugar.

Obviously, added sugar isn’t the only issue with the modern diet. Vegetable oils like soybean oil, safflower oil, and sunflower oil also drive inflammation and create conditions ripe for obesity. But sugar might be worse.

Even groups like the American Heart Association and the CDC, typically behind the curve on nutrition, caution against sugar. The CDC, for example, advises us to limit added sugars to less than 10% of daily calories. But 10% of total energy intake is pretty high. On a 2000 calorie diet, that’s 12 teaspoons of sugar! Imagine spooning that down.

We’re exceeding that mark. Recent estimates peg the average American adult at 17% of daily calories from added sugar. So where is all this refined sugar coming from? Well, when you look at the data, it’s not that we eat too much sugar, but rather that we drink too much in sodas, fruit juices, and sports drinks. Overconsumption of these sugar-laden beverages is likely a major driver in the American “diabesity” (obesity + diabetes) epidemic.

How? Because you can drink sugar all day and not be full. Sugar is (arguably) addicting… There is much gnashing of teeth on the interwebz about this. Some say sugar is worse than opiates, while others just suggest folks measure their soda intake.

What’s not controversial is that sugar is easy to over-consume. Folks already tend to like it a bit more than they should. Add to this that you can down a 2 liter bottle of soda for less than the price of most bottled water, and it’s not surprising at all. Significantly over-consuming calories of any kind is terrible for our metabolism, and puts you in fat-storage mode. Sugar just happens to be the area where most people over-step.

You probably already knew that sugar is bad for you. But I wrote this article to really dive into why. Stick with it and I think you’ll learn something new. And at the end, I’ll talk about the healthier, sugar-free ways to satisfy your sweet tooth.

What Is Sugar?

Most people, when they talk about sugar, are talking about sucrose. Also known as table sugar, sucrose is a disaccharide (di = two, saccharide = sugar) that’s composed of glucose and fructose.

Glucose and fructose are monosaccharides, or simple sugars, and they represent the two main ways in which plants store energy. (Plants store it, we eat it!). Other sugars include galactose, lactose, and maltose.

All sugars are carbohydrates, but not all carbs are sugars. Fiber, for instance, is a carb but not a sugar.

When I discuss the problems with sugar, I’m mostly discussing the problems with sucrose, fructose, and high fructose corn syrup. High fructose corn syrup is a liquid sweetener similar to sucrose, and it’s the crap in our beverages making us fat.

That fructose makes us fat makes sense from an evolutionary perspective. Our ancestors evolved through long stretches of scarcity, and fruit was a rare treat. The humans who could efficiently convert fructose to fat survived. The rest did not.

Today, our liver still converts fructose to fat like gangbusters. What was good then isn’t so good now.

Sugar, Insulin Resistance, and Inflammation

Eating too much sugar has been linked to nearly every chronic disease. But before exploring these links, I want to talk about insulin resistance and inflammation.

When you understand how sugar consumption likely contributes to insulin resistance and inflammation, you’ll understand the roots of why sugar is harmful.

Sugar Drives Insulin Resistance

When you eat sugar, that sugar ends up in your blood as blood sugar, or blood glucose. The more sugar you eat, the higher your blood sugar gets.

High blood sugar is a dangerous, inflammatory state—and your body knows it. So when blood sugar gets high, your pancreas releases insulin to clean up the mess.

Insulin is your blood sugar boss. It tells cells in your liver and muscle tissue to store away excess blood sugar as glycogen (your safe storage form of glucose) for later use.

But glycogen stores fill up quickly, and when they do, insulin is forced to store excess blood sugar as body fat. On a high-sugar diet, this gets out of hand FAST. Blood sugar keeps spiking, insulin keeps getting released, and the fat stores rapidly accumulate. It’s a vicious cycle particularly when we consider how this situation leads to a general tendency to over eat.

The inability of insulin to store blood sugar as glycogen is known as insulin resistance, and it’s the hallmark of type 2 diabetes. Along with diabetes, insulin resistance is also linked to heart disease, cancer, fatty liver disease, Alzheimer’s, and many other conditions. And high sugar diets are largely to blame.

Sugar Drives Inflammation

If you want to live a long, healthy life, you’ll want to keep chronic inflammation low. Along with insulin resistance, chronic inflammation is a defining feature of unhealthy aging.

Inflammation, by the way, refers to a low-grade immune response in the absence of specific disease. Think of it as immune system confusion. Damaging confusion.

Here’s where sugar comes in. High sugar diets have been correlated with chronic inflammation—specifically, with high circulating levels of an inflammatory particle called C-reactive protein, or CRP.

How, exactly, does consuming sugar increase inflammation?

  • By increasing blood sugar levels (hyperglycemia is an inflammatory state)
  • By feeding pathogenic gut bacteria and increasing gut permeability (leaky gut)
  • By decreasing the production of ketones, which have anti-inflammatory effects
  • By causing excess fat storage, which leads to inflammation

The takeaway is: Eating sugar increases inflammation, and inflammation drives chronic disease.

8 Reasons To Avoid Sugar

Now that you have a framework for understanding the dangers of sugar, let’s look at some specific problems linked to excess sugar intake.

#1: Obesity

In the United States, obesity has reached epidemic proportions. Over 30% of Americans are obese, and hundreds of thousands die each year from obesity-related disease.

These diseases include heart disease, diabetes, cancer, and neurodegenerative disease. Obesity, it’s clear, is a significant risk factor on a patient’s chart.

Sugar takes a large chunk of the blame. Study after study indicates that the more sugar someone consumes, the more weight they gain. Especially if that sugar is coming from liquid sources.

What drives sugar-induced weight gain? The simple explanation is that added sugar increases your calorie intake, but there’s more to it than that.

Another explanation is that sugar isn’t satiating. In other words: 100 calories of high fructose corn syrup doesn’t fill you up like 100 calories of saturated fat. Sugar never satisfies, so you always want more.

Finally, sugar consumption creates insulin resistance, which activates fat-storage mode. Put it all together and you have a formula for obesity.

#2: Type 2 Diabetes

Closely linked to obesity is type 2 diabetes, a metabolic disorder defined by high blood sugar, high insulin, high blood pressure, and excess fat mass.

If you want to induce type 2 diabetes in a healthy person, simply feed them sugar through a straw. Soon they’ll develop insulin resistance and be storing fat like crazy, like huge swaths of the American population.

In one study following over 90,000 women over eight years, consuming more than one sugary beverage per day correlated with an 83% higher risk of developing type 2 diabetes vs. consuming less than 1 sugary beverage per month. Pretty significant.

#3: Heart disease

Everything we’ve talked about so far—insulin resistance, inflammation, obesity, and diabetes—also increases one’s risk of heart disease.

When I say heart disease, I’m talking about atherosclerosis, or the buildup of plaque on the arterial wall that eventually leads to stroke or heart attack. Globally, heart disease is the number one killer.

According to a review in the journal Nutrients, a person’s risk of heart disease rises by 10 to 20 percent for each additional sugary beverage consumed daily. Other data from The Framingham Heart Study found that drinking more than one sugary beverage per day was linked to high blood pressure and high triglycerides, both heart disease risk factors.

#4: Cognitive decline

Multiple lines of evidence point to high sugar diets impairing cognition. When you look at population data, for instance, you find more age-related cognitive decline at higher sugar intakes.

In animals, researchers have found that excess sugar intake harms the hippocampus, a brain region involved in memory processing. Fructose, sucrose, and maltodextrin (different forms of sugar) all appear to have negative effects.

Sugar also impairs brain function in humans. In one study, drinking a glucose or sucrose solution caused declines in mental performance compared to placebo.

#5: Cancer

Compared to healthy cells, many cancer cells love metabolizing sugar (glucose) for energy. This is called the Warburg effect, and it’s likely why the ketogenic diet (which lowers blood glucose) is therapeutic for certain cancers.

Eating sugar, in other words, likely feeds cancer. It also feeds cancer by increasing inflammation, which creates conditions ideal for cancer progression.

Fructose is an especially bad actor here. In mice, the equivalent of one daily soda’s worth of high fructose corn syrup accelerated the progression of colon cancer.

To be clear, cancer is an extremely confusing condition. And cutting out sugar won’t cure it. But with the data in hand, it seems like a solid risk-reduction play.

Check out Peter Attia’s podcast with Rick Johnson for more on the dangers of fructose. Both these guys are super smart MDs, and they cover the topic brilliantly.

#6: Leaky gut

High sugar diets feed pathogenic bacteria and fungi in the gut. These bad bacteria, in turn, damage the fragile gut barrier, creating a condition called leaky gut.

When someone has leaky gut, food particles leak through the intestinal wall and into the blood. The immune system then attacks these food particles, creating more damage, more leaky gut, and the cycle continues.

The good news is: Low-carb, low-sugar diets can starve bad bacteria and allow your gut to heal. If you want to go deep on this topic, read Healthy Gut, Healthy You by Dr. Michael Ruscio. I highly recommend it.

#7: Cavities

Your dentist was right all along. Sugar is bad for your teeth.

In the mouth, sugar feeds bacteria (like Streptococcus mutans) that cause tooth decay. Unsurprisingly, higher sugar consumption is linked to higher rates of cavities in children.

#8: Kidney disease

Imagine drinking two liters of Coke after four hours of heated exercise. That’s what twelve healthy adults did in a recent study published in the American Journal of Physiology.

The results? A variety of biomarkers (like increased creatinine) suggesting the participants had sustained kidney injury.

To bolster this result, observational data on 3,003 African Americans has linked higher consumption of sugary beverages to higher rates of chronic kidney disease.

Choosing A Sugar Alternative

A healthy diet needs to be low in sugar. That much is obvious. But does that mean a healthy diet can’t be sweet?

Not necessarily.

The most popular sugar substitutes are artificial sweeteners like aspartame, sucralose, and saccharine. And while these compounds are probably healthier than sugar, they’ve also been linked to increased diabetes risk.

Sugar alcohols like xylitol, sorbitol, and erythritol hold up better under scrutiny, and may even have antioxidant effects. The downside, however, is that they often cause GI distress.

This brings us to stevia, a zero-calorie sweetener derived from the leaves of the stevia rebaudiana plant. Instead of driving diabetes, stevia appears to blunt the post-meal rise in blood sugar and insulin levels, compared to sugar and artificial sweeteners.

Stevia also has been shown to:

  • Lower inflammation
  • Improve oral health
  • Exert antioxidant effects
  • Lower blood pressure
  • Reduce liver damage

    To be clear, too much stevia might not be optimal. It could bump up insulin a bit, for instance. But since stevia is about 300 times sweeter than sugar, you don’t need much of it!

    Overall, I believe stevia is a solid option for sweetener. That’s why we use it for the flavored versions of LMNT. (Raw Unflavored has just the electrolytes – no sweeteners of any kind)

    Steering Clear Of Sugar

    It’s a cliche, but I’ll say it anyway: You are what you eat.

    When you eat a high-sugar diet, that sugar ends up in your blood. Then you develop insulin resistance, inflammation, and the full spectrum of diseases that come along for the ride.

    But giving up sugar doesn’t mean giving up sweetness. Consider a zero-sugar sweetener like stevia to appease your sweet tooth without derailing your health.

    The longer you steer clear of sugar, the easier it gets. The addiction wears off, and you can make coolheaded decisions to optimize your wellbeing. And that, I think you’ll agree, is a very good place to be.

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