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  • Denise Scott

The Sweet Toxicity of Sugar

Updated: Aug 7, 2023

Sugar can be tasty but too much is toxic

Now that you have ideas for healthy sweet treats from last week, I will tell you the dangers of too much sugar this week. Most of us are pretty sweet on sugar, but research reveals a bittersweet reality!

Sugar occurs naturally in any food that contains carbohydrates - fruits, vegetables, grains, and dairy. Consuming these natural forms of sugar are healthy since these types of food also contain fiber, antioxidants, vitamins, and minerals. In fact, research shows that eating a diet rich in these natural, whole foods can prevent heart disease, diabetes, and some cancers, as discussed in previous blogs.

The danger is consuming foods with added sugar, those sweetened beverages and processed foods manufactured with additional sugar (see post on carbohydrates). The list is long and includes the following:

Cakes, candy, cereals, cookies, breads, jams, jellies, pastries, flavored yogurts, refined grains, and less obvious foods such as ketchup, salad dressings, cured meats, soups, and alcohol as well as ALL sugar-sweetened beverages including: sodas, sweetened teas, sports drinks, energy drinks, flavored coffees, juices and fruit drinks.

One teaspoon of sugar contains 4 grams of carbohydrate which equals 16 calories (there are 4 calories per one gram carbohydrate).

A single 12-ounce soda contains 9-10 teaspoons of sugar and about 150 calories.

When checking the nutrition label on a food item, sugars are listed under carbohydrates, and the amount is given in grams.

Example of a nutrition label on a can of soda : the carbohydrates = the sugars

For instance, a can of soda lists “total carbohydrates” with sugars listed below the carbs.

For a can of soda with 9 teaspoons of sugar, the total carbohydrates and sugars are both listed as 36 grams :

(9 teaspoons x 4 carbohydrates/teaspoon).

In this case, there are 39 grams or almost 10 teaspoons of sugar.

The calories = the number of grams of sugar x 4 calories/gram of sugar = 39 x 4 = 156 calories per can of soda. (I'm not sure on this label how they came up with 140 instead of 156, their math doesn't add up!)

Drinking one 12-ounce soda daily for a week adds 1092 calories a week.

Drinking one 20-ounce soda daily for a week adds 1680 calories a week, or about ½ pound of weight gain a week or 2 pounds a month! (It takes 3500 calories to gain a pound).

It is no wonder I've seen children gain 10-20 pounds over a few months! I always reviewed first with these patients what they drank before any concerns about their eating habits. Those that drank sugar-sweetened beverages daily were guaranteed to lose weight simply by changing that one consumption habit.

The effects of a high sugar diet on weight gain, obesity, insulin resistance, and metabolic syndrome are well known. I want to emphasize two other serious health issues.

First I will review the effects on the heart and next the effects on the liver.

Sugar and the Risk of Heart Disease

The American Heart Association (AHA) recognizes the risk of a high sugar diet on the heart and cardiovascular system. Diets high in sugar lead to high triglycerides that lead to heart disease.

Because of this, the AHA recommends no more than

6 teaspoons of added sugar (25 grams) a day and no more than

8 ounces of sugary beverages A WEEK for children 2-18 years.

A high-sugar diet increases the risk of dying from heart disease. If those habits begin at a young age, the risk already increases by young adulthood. High amounts of added sugar increase the risk of inflammation, obesity, type 2 diabetes, high blood pressure, and fatty liver disease, all which increase the risk for heart disease.

The following is a list of ingredients that may not be called sugar but are sources of added sugar and can be found on food labels:

Corn syrup and high-fructose corn syrup (HFCS)

Corn sweetener

Fruit juice concentrate



Maple sugar

Brown sugar

Malt sugar

Sugar molecule names that end in “-ose”: sucrose, glucose, maltose, dextrose, fructose

If these are listed in the first three ingredients on a label, be wary. A food label typically lists the ingredients in order from the highest to the lowest concentrations.

The liver metabolizes excess sugar into triglycerides and fat, which brings us to…..

Sugar and the Risk of Liver Disease

When we eat sugar, much of it is broken down into glucose which is absorbed and used as energy. Excess glucose is converted in the liver to fat which is partly stored in the liver. The liver metabolizes some sugars similar to alcohol. Fructose and high-fructose corn syrup are made into fat in the liver. Diets high in processed foods are high in these compounds. The fat metabolized from them builds up in the liver, eventually leading to liver disease. This disease is termed non-alcoholic fatty liver disease (NAFLD).

Previously, fatty liver disease was primarily seen in alcoholics and termed alcoholic liver disease. NAFLD distinguishes the cause of fatty liver, especially since it is now seen in children. Yes, children CAN develop NAFLD from consuming too much fructose and HFCS in processed foods and too many sugar-sweetened beverages! Obesity is a risk for NAFLD and I saw patients with this in practice. Ultimately, the worst complication of NAFLD is cirrhosis (just like in alcoholics) and liver failure.


Sugar alcohols, such as xylitol, erythritol, sorbitol, and maltitol, are used in processed foods to sweeten the food while reducing the calories. The chemical structure of sugar alcohols partly resembles sugar and partly resembles alcohol, though there are no alcohol effects. Sugar alcohols are not as well absorbed as natural sugars and can lead to gas, bloating, and loose stools. Even though sugar alcohols may lower calories compared to regular sugar, these still can affect the liver.

A sugar crash waiting to happen!

A third issue in children is the effects that sugar has on behavior. Has your child ever been hyper after consuming a sugar load of sweets or soda? Mine were bouncing off the walls! This is followed by the sugar crash - when the blood sugar rises rapidly, it can also fall rapidly due to the rise in insulin levels that follows the rise in blood sugar. The drop in blood sugar causes irritability, fatigue and shakiness. This yo-yo rise and fall in blood sugar can definitely have a bearing on kids' behavior and is best to be avoided. When this occurs frequently, it leads to weight gain and insulin resistance. A diet high in fiber and natural, wholesome foods will prevent this.

The bottom line is that sugar, consumed in excess, leads to fat, primarily triglycerides, which can cause heart and liver disease. Prevent this by eating a diet rich in natural, unprocessed, whole foods with natural sugars from fruit, vegetables, whole grains and dairy. Limiting or avoiding processed foods and sugar-sweetened beverages will keep your heart and liver happy!

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