Avoid the sugar that leads to fatty liver disease, cancer and heart disease

It’s way too easy to eat more than your fair share of sugar. Case in point?

Today, I had a microwavable pad Thai dish for lunch. As I was waiting for the microwave to ding, I read the nutrition label. Big mistake.

It turns out my pad thai contained 29 grams of sugar… 29 grams! Now, I knew microwavable pad thai wasn’t exactly on par with wild Alaskan salmon served over a bed of fresh greens. But I didn’t expect it to contain more than my recommended dosage of added sugar for the entire day (25 grams for women).

I vowed to never buy that pad thai again because I know how easily added sugar can stack up to subpar health. Eating too much sugar contributes to weight gain, acne, and depression. It also increases your risk of type 2 diabetes, heart disease, and cancer.

Related: Sugar’s cancer-causing secret exposed

But there’s something I need to remember before I get all worked up about eating too much sugar in my pad thai….

Not all sugar is created equal. Our bodies handle different types of sugar, well, differently. And the effect isn’t always bad.

In fact, a new study shows that one type of sugar sets you up for a dangerous health condition… and another type helps protect you from it.

High-fructose diet fuels fatty liver disease… and glucose fights it

When your fat cells get overloaded with fat, they send this fat to other parts of the body, including your liver. Eventually, this causes fatty liver disease, which can lead to liver failure.

But there may be one way to reduce the odds of developing this dangerous liver condition — swap out fructose for glucose.

You heard me. Choose one type of sugar over the other. Here’s why…

A series of new studies show that fructose makes it extra hard for your liver to process fat. Glucose, on the other hand, makes it a little easier.

In the studies, researchers from Joslin Diabetes Center looked at how a variety of diets affected liver health in animals: a regular diet, a high-fructose diet, a high-glucose diet, a high-fat diet, a high-fat diet with high fructose, and a high-fat diet with high glucose.

Next, they looked for signs of a fatty liver. Specifically, they looked for acylcarnitines in liver cells. Acylcarnitines are created when the liver burns fat. High acylcarnitine levels are bad because they mean the liver is burning a lot of fat. In other words, the liver is getting fatty.

Animals on the high-fat, high-fructose diet had the most acylcarnitines. But do you know what’s truly surprising? Animals who ate the high-fat, high-glucose diet had fewer acylcarnitines than animals eating just a high-fat diet. That means glucose helps the liver burn fat more efficiently.

What else did researchers find?

Animals on the high-fat, high-fructose diet had less CPT1a, an enzyme that the liver uses to burn fat. Not having enough CPT1a means the mitochondria (energy center of your cells) can’t do their job. Researchers even looked at the mitochondria in animals who ate the high-fat, high-fructose diet and sure enough, they were a hot mess. But mitochondria in the high-fat, high-glucose diet group looked normal and healthy.

“The most important takeaway of this study is that high-fructose in the diet is bad. It’s not bad because it’s more calories, but because it has effects on liver metabolism to make it worse at burning fat. As a result, adding fructose to the diet makes the liver store more fat, and this is bad for the liver and bad for whole-body metabolism,” says C. Ronald Kahn, Chief Academic Officer at Joslin and the Mary K. Iacocca Professor of Medicine at Harvard Medical School and lead author on the study. “Surprisingly, when you switch the sugar in the diet from fructose to glucose, even though they’re both equally caloric, the glucose doesn’t have that effect. In fact, if anything, overall metabolism is somewhat better than if they just were on a plain high-fat diet.”

Eat less of these fructose-containing foods

How do you know what foods contain fructose so you can cut back on this liver-harming sweetener? Well, here are a few sources:

  • Table sugar
  • Honey
  • Agave nectar
  • Maple syrup
  • Molasses
  • Caramel
  • Brown sugar
  • Palm sugar
  • Fruit
  • Some vegetables
  • Processed foods and drinks that contain high-fructose corn syrup

Now, just like not all sugar is created equal, not all sources of fructose are created equal. Why?

The high-fructose corn syrup in a can of soda, for example, gives you a heaping dose of fructose without any fiber. Fruit juice does the same thing. Fiber slows down sugar digestion… which means it doesn’t hit your body all at once and cause a blood sugar spike. An apple, on the other hand, gives you a little fructose and a lot of fiber. Fruits and vegetables also contain antioxidants that counteract the inflammation caused by fructose. So, you don’t need to cut out whole foods like fruit and vegetables (which contain some fructose but lots of fiber), so much as sweet drinks and processed foods.

No matter what type of sugar you’re eating (even if it’s liver-supporting glucose), keep your daily intake of added sugar to a reasonable amount. Men can get up to 150 calories per day (37.5 grams or 9 teaspoons) from added sugar and women can get up to 100 calories per day (25 grams or 6 teaspoons) from added sugar. That means no more microwavable pad thai for me anytime soon.

Editor’s note: Trying to eat and be healthy can seem overwhelming. Especially when you see news like this every day! Deciphering the good from the bad is impossible. But adopting a part-time health nut lifestyle is as simple as cracking open Dr. Cutler’s guide on how to attain your best health ever, without extreme diets, dangerous pills or brutal workouts. Click to learn how!


  1. High-fructose and high-fat diet damages liver mitochondria, study finds — MedicalXpress
  2. Daily Intake of Sugar — How Much Sugar Should You Eat Per Day? — Healthline
  3. 11 Reasons Why Too Much Sugar Is Bad for You — Healthline
  4. Evidence Shows Some Sugars Are Worse Than Others; Fructose Tops the List — Healthline
  5. Is fructose bad for you? — Medical News Today


Jenny Smiechowski

By Jenny Smiechowski

Jenny Smiechowski is a Chicago-based freelance writer who specializes in health, nutrition and the environment. Her work has appeared in online and print publications like Chicagoland Gardening magazine, Organic Lifestyle Magazine, BetterLife Magazine, TheFix.com, Hybridcars.com and Seedstock.com.