Why You Should Never Quit Fruit During a Low-Carb Diet, According to Science

One of my patients – who was obese, uncontrolled diabetes and the cost of her medication – agreed in June 2019 to adopt a whole food plant-based diet.

Excited for the challenge, she did a great job. She increased her intake of fresh fruits and vegetables, stopped eating sweets, crackers and cakes, and reduced foods from animal sources. Over the course of six months, she lost 19 pounds and her HbA1c — a measure of average blood sugar — dropped from 11.5 to 7.6 percent.

It has been working so well, I was expecting HbA1c to keep dropping and it would be one of our vegan successes that reversed my diabetes.

The three-month follow-up visit in March 2020 has been canceled due to the COVID-19 lockdown. When I finally saw her back in May 2021, she had regained some weight and her HbA1c had risen to 10.4 percent.

She explained that her doctor and diabetes nurse had told her that she was eating a lot of “sugar” in a plant-based diet.

She was advised to limit carbohydrates by reducing starchy fruits and vegetables and eating more fish and chicken. Sugar-free candy, cookies, biscuits, and artificial sweeteners were encouraged. In the face of conflicting medical advice, I’ve fallen back on the conventional wisdom that “sugar” is bad and should be avoided whenever possible, especially if you have diabetes.

I am a physician, board certified in Preventive Medicine with the Lifestyle Medicine Clinic at Morehouse Healthcare in Atlanta. This emerging medical specialty focuses on helping patients make healthy lifestyle behavior modifications.

Patients who follow a whole-food plant-based diet increase their carbohydrate intake and often see a reversal of chronic diseases including diabetes and high blood pressure. In my clinical experience, myths about “sugar” and carbohydrates are common among patients and health professionals.

fruit vs sugar

Your body runs on glucose. It is the simple sugar that cells use for energy.

Glucose is the molecular building block of carbohydrates, and one of the three essential nutrients. The other two are fat and protein. Starches are long, branched chains of glucose.

(Trest/Getty Images)

above: These molecules – glucose, fructose and galactose – are the three types of simple sugars found in starches, fruit and milk.

Natural carbohydrates go in packages rich in nutrients such as fruits, vegetables, whole grains, nuts and seeds.

(Trest/Getty Images)

above: Simple chains of sugar molecules linked together form starches and other carbohydrates.

Humans evolved to crave sweet tastes to obtain the nutrients needed to survive. A daily supply of vitamins, minerals, and fiber is needed because our bodies cannot make them. The best source of these substances for our ancient ancestors was sweet, ripe and tasty fruit.

In addition, fruit contains phytonutrients, antioxidants, and chemicals that are produced only by plants. Phytonutrients like ellagic acid in strawberries have cancer-fighting properties and promote heart health.

Refined sugars, on the other hand, are highly processed and stripped of all nutrients except for calories. It is a concentrated form of carbohydrates. The food industry produces refined sugars in many forms. The most common are sucrose crystals, which you define as table sugar, and high-fructose corn syrup, which is found in many processed foods and sweetened beverages.

If you’re constantly satisfying your craving for sweets with foods that contain refined sugar—rather than the nutrient-rich fruits at the core of this evolutionary craving—you may not be getting all the nutrients you need.

Over time, this deficiency may create a vicious cycle of overeating that leads to obesity and the health problems associated with obesity. Women who eat a lot of fruit tend to have lower rates of obesity.

sugar toxicity

Refined sugars are not directly toxic to cells, but they can combine with proteins and lipids in food and in the bloodstream to produce toxic substances such as advanced glycation end products (AGEs). High blood glucose levels may result in low-density lipoprotein (LDL) glycoprotein. High levels of these and other glucose-related toxins are associated with an increased risk of developing a wide range of chronic health problems, including cardiovascular disease and diabetes.

The disease most closely associated with diabetes is type 2 diabetes. An astonishing number of people, including health professionals, mistakenly believe that eating sugar causes type 2 diabetes. This myth leads us to focus on lowering blood sugar and “counting carbohydrates” while ignoring the real cause: the gradual loss of function of the beta cells in the pancreas. At diagnosis, the patient may have lost 40 to 60 percent of the beta cells responsible for insulin production.

Insulin is a hormone that controls the amount of glucose in the bloodstream by blocking glucose production in the liver and pushing it into fat and muscle cells. Loss of beta cell function means not enough insulin is produced, which leads to the high blood glucose levels characteristic of type 2 diabetes.

Beta cells contain low levels of antioxidants and are vulnerable to attack by oxidative, food, and weather free radicals. The antioxidants in the fruit can protect the beta cells. Researchers have found that eating whole fruit reduces the risk of developing type 2 diabetes, and those who eat the most fruit have the lowest risk.

Detoxing from sugar

People interested in losing weight and improving health often ask if they should “detox with sugar.” In my opinion this is a waste of time, because sugar cannot be eliminated from the body. For example, if you only eat grilled chicken breast, the liver converts protein into glucose in a process called gluconeogenesis.

Low-carb diets may lead to weight loss, but at the expense of health. Diets that significantly reduce carbohydrates are associated with nutrient deficiencies and an increased risk of death from any cause. On low-carb ketogenic diets, the body breaks down muscle and converts protein into glucose. A lack of fiber causes constipation.

Eliminating foods sweetened with refined sugar is a worthy goal. But don’t think of it as a “detox” – it should be a permanent lifestyle change. The safest way to continue your “detox” of refined sugar is to increase your intake of nutrient-rich fruits and vegetables. Once you’ve eliminated refined sugar, you’ll likely find that your taste buds have become more sensitive – and appreciative – to the natural sweetness of fruits. Conversation

Jennifer Rock, MD, assistant professor of community health and preventive medicine, Morehouse School of Medicine.

This article has been republished from The Conversation under a Creative Commons license. Read the original article.


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