5 Science-Backed Studies That Show How a High-Sugar Diet Damages Health

High-Sugar DietYou rarely hear anything positive about sugar. No wonder! It’s a prime major contributor to expanding waistlines and health problems. Plus, sugar’s role in the obesity epidemic is well documented. The average American consumes around 17 teaspoons of sweet stuff daily. Why? Not only is the taste of sweet pleasing to the tongue, but studies show the human brain responds to it in a way that makes you want to consume more.

What is sugar? It’s a carbohydrate; the sugar molecule is composed of carbon, hydrogen, and oxygen atoms. In nature, sugar molecules are found in plants and manufactured by living organisms. In the human body, it circulates mainly as glucose.

Most of the sugar we eat is sucrose, which is a disaccharide–a combination of two simple sugars. There are about 4 grams of sugar in a teaspoon of granulated sugar, or about 16 calories. However, sugar lacks nutrients, making it a top source of empty calories in the diet.

Studies show a diet high in sugar may increase your risk of future health problems. Here are five problems it causes, supported by research.

Sugar is Bad for Your Heart

Most of the effects of sugar on heart health come from short-term studies. Unfortunately, there are few reliable studies looking at the long-term impact of a diet high in sugar on heart health. Besides, it’s hard to conduct such research due to confounding factors that influence the results.

According to the journal Circulation, short-term studies show that consuming a diet high in sugar increases blood triglycerides and lowers HDL-cholesterol (the good form of cholesterol), both of which increase the risk of cardiovascular disease. Plus, a diet high in sugar contributes to insulin resistance, another risk factor for cardiovascular disease. The best eating plan for heart health is a whole food diet high in fiber and plant-based foods, and low in sugar and refined carbohydrates.

Sugar Contributes to Weight Gain and Obesity

Studies also link a diet high in sugar with weight gain and a greater risk of obesity. The strongest evidence is for sugar-sweetened beverages, particularly soft drinks.

A study published in Diabetes Care showed that sugar-sweetened drinks are linked to weight gain and obesity (Malik, Schulze, and Hu, 2006). It’s not surprising, since soft drinks cause rapid spikes in blood sugar and insulin, and that sugar ends up on your waistline or as unhealthy fat on your liver. Plus, drinking a soft drink doesn’t satisfy hunger in the way whole, nutritious food does, so you consume more calories when you drink these fizzy beverages.

A High-Sugar Diet Contributes to Skin Aging

Your skin is the largest organ in your body, and shows visible signs of aging.  If you eat a diet high in sugar and it leads to more glucose in your bloodstream, the sugar can damage two key proteins in your skin called elastin and collagen. These are the proteins that keep your skin firm, youthful, and wrinkle-free.

A study published in Clinics in Dermatology shows that glucose in sugar creates advanced-glycation end-products (AGEs) that damage collagen and elastin and contribute to wrinkles and skin sagging. So, it’s not just external factors, like cigarette smoke, air pollution, and smoking, that harm your skin; a high-sugar diet can too. Keep wearing a sunscreen to reduce skin aging, but cut back on sugar too.

Sugar Contributes to Insulin Resistance and Type 2 Diabetes

The link between diets high in sugar and type 2 diabetes is indirect. The risk of type 2 diabetes increases with weight gain. People who are obese are at a significantly greater risk of developing this chronic health condition. What’s the fastest way to gain weight? Eating too many calories, especially empty calories from sugar. Added sugar causes blood glucose and insulin spikes, which make it easier for your body to store more body fat.

As your weight rises, it places more stress on your pancreas to make more insulin. This, in turn, increases your risk of type 2 diabetes. A study published in Diabetes Care points out that high-sugar beverages, like soft drinks, is linked with insulin resistance and type 2 diabetes.

Sugar Addiction

Studies in animals show that sugar is addictive. When you consume foods high in sugar, it activates reward centers in the brain that make you feel good. It should come as no surprise that you want more of those pleasurable feelings, so you eat or drink more sugar.

Some experts liken sugar addiction to drug and alcohol dependence. However, this isn’t conclusively proven in humans. Yet a study in Neuroscience and Biobehavioral Reviews shows this occurs in rats and they become sugar dependent as a result. Don’t let sugar hijack your brain!

The Bottom Line

Now you know why sugar does your body no favors. If you can’t go cold turkey, gradually scale back on the amount of sugar in your diet. Also, avoid refined carbohydrates, as they have some of the same effects on your body as sugar. What you eat plays a major role in your health – choose wisely.


  • Avena, N. M., Rada, P., & Hoebel, B. G. (2008). Evidence for sugar addiction: Behavioral and neurochemical effects of intermittent, excessive sugar intake. Neuroscience & Biobehavioral Reviews, 32(1), 20-39. Retrieved 6 26, 2021, from ncbi.nlm.nih.gov/pmc/articles/pmc2235907
  • Danby, F. W. (2010). Nutrition and aging skin: sugar and glycation. Clinics in Dermatology, 28(4), 409-411. Retrieved 6 26, 2021, from ncbi.nlm.nih.gov/pubmed/20620757
  • Howard, B. V., & Wylie-Rosett, J. (2002). Sugar and Cardiovascular Disease A Statement for Healthcare Professionals From the Committee on Nutrition of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association. Circulation, 106(4), 523-527. Retrieved 6 26, 2021, from ahajournals.org/doi/full/10.1161/01.cir.0000019552.77778.04
  • Malik, V. S., Popkin, B. M., Bray, G. A., Després, J.-P., Willett, W. C., & Hu, F. B. (2010). Sugar-Sweetened Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes: A meta-analysis. Diabetes Care, 33(11), 2477-2483. Retrieved 6 26, 2021, from https://ncbi.nlm.nih.gov/pmc/articles/pmc2963518
  • Malik, V. S., Schulze, M. B., & Hu, F. B. (2006). Intake of sugar-sweetened beverages and weight gain: a systematic review. The American Journal of Clinical Nutrition, 84(2), 274-288. Retrieved 6 26, 2021, from ncbi.nlm.nih.gov/pmc/articles/pmc3210834.

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