While a varied and balanced diet including fruits and vegetables does help to support the immune system in general, there is no evidence to suggest that special diets, consumption of particular foods, or taking vitamin, mineral, or herbal supplements will prevent, treat or cure COVID-19. For patients with type 2 diabetes, using medications, diet controls (intentionally eating for your condition, like controlling carbohydrate intake and limiting sugar), and exercise to keep blood sugar levels within a normal range has been associated with better outcomes in patients with COVID-19.

While diets high in sugar have been shown to impact health, it is not well understood how much added sugar is needed to cause health problems. Studies show that people who consume diets that are high in sugar are more likely to be overweight or obese and have other health problems like insulin resistance (where their bodies are not able to use sugar correctly), type 2 diabetes, high cholesterol, kidney disease, or fatty liver disease than people who consume little added sugar. In addition, sugar has been linked with inflammation and poor immune function in the body, especially when a person has insulin resistance or excess body fat. Researchers do not know how much, what type, or under which conditions sugar may cause problems in the short or long term.  

Sugar is a natural part of all foods that have carbohydrates, including fruits, vegetables, grains, beans and legumes, and dairy products. These foods are all part of a well-balanced diet. When looking at diet, consuming sugars as part of unprocessed, whole foods is not usually a concern because of the other health benefits that come from those foods. Added sugar, however, is a significant concern.

The World Health Organization (WHO) guidelines advise that adults and children limit their daily intake of added sugar to less than 10% of total calories (about 50 grams or about 12 teaspoons) to prevent excess weight gain, type 2 diabetes, heart disease, and dental cavities. Other leading health organizations including the American Heart Association recommend further reducing added sugar (no more than 9 teaspoons or 36 grams of sugar per day for men; no more than 6 teaspoons or 25 grams per day for women).  One 12-ounce soda, for example, has 8 teaspoons (about 32 grams) of added sugar.

There are many different kinds of sugar used in food preparation and processing, including white or brown sugar, honey, syrups (i.e. maple, rice, golden, corn, agave), molasses, coconut sugar, fruit juice concentrate, malt sugar, and others. Other common sources of dietary sugar are often called “hidden” sugar because they are included in processed foods yet can be difficult to find on food labels, if the food is labeled at all. Examples of “hidden” sugars include sugar sweetened beverages (i.e. cola, soda, flavored milk products, some juices) and processed or packaged foods (including products cookies, cereal products, sweetened dried fruits, sauces and condiments like ketchup or salad dressing, snack foods, and candies).

If possible, the WHO has said that there may be added health benefits if people are able to decrease their intake to less than 5% (about 25 grams or about 6 teaspoons) per day.