How Much Fruit Is Too Much Fruit?

How Much Fruit is Too Much Fruit? Graphic © healthpowerboost.com. Background photo: Pixabay (PD)

Fruit intake has long been associated with a healthy diet and healthy lifestyle choices. However, is there a healthy limit to how much fruit we can actually eat? Isn’t having too much of anything bad for you?

Dr. Michael Greger discusses how much fruit is too much fruit – in particular as it relates to blood sugar and insulin – in one video on his popular Youtube channel, Nutrition Facts.

Berries Found To Improve Insulin Response And Hyperglycemia

Data from the World Health Organization reports that over 422 million people have diabetes all over the world. ^[1] Diabetes is characterized by persistently high blood sugar, because of the body being resistant to insulin. Insulin works by stimulating our cells to absorb glucose or sugar from food. When the cells become resistant to insulin, glucose remains circulating in the blood stream, a condition called hyperglycemia. Persistently high blood sugar levels cause weight gain, poor wound healing, and in worst cases, kidney failure and blindness. ^[2]

The first study covered by Dr. Greger was published in 2013 by Törrönen, et. al. and reported the antioxidant effects of berries on postprandial hyperglycemia after eating bread. ^[3] White bread is known to cause high postprandial glucose and stimulate the insulin response. Rye bread is similar, but postprandial glucose is lower. Because previous in-vitro studies showed how the polyphenols from berries was able to reduce digestion and absorption of starch and reduce postprandial hyperglycemia, the researchers conducted a trial involving 3 randomized, controlled, crossover studies by adding 150grams of berries with white and rye bread (with 50 grams of starch).

The results of the studies revealed that the following improved the body’s insulin response:
– Strawberries, bilberries, lingonberries, and chokeberries with white bread
– A berry mixture with strawberries, bilberries, cranberries, and blackcurrants with both white and rye bread

On the other hand, the following was able to reduce postprandial hyperglycemia:
– Strawberries, by 39%
– The berry mixture, by 38% with white bread and by 19% with rye bread

Similarly, Blacker, et. al. reported in the same year that blueberries in particular exhibited strong antioxidant properties due their phenolic content, not their fructose or ascorbate. ^[4] The study revealed that blueberries were able to reduce postprandial oxidation after a high-carbohydrate, low-fat breakfast. The more blueberries were included in the meal, the higher the antioxidation effects.

Diabetics And Fruit Intake

The real lowdown on fruit and hyperglycemia was seen in a study by Christensen, et. al. in 2013. The researchers focused on the effects of high dose and low dose fruit intake on the HbA1C levels of newly diagnosed type 2 diabetics; HbA1C being one the standards used in diagnosing diabetes. The study involved 63 participants with one group receiving 125 grams of fruit and the other 51 grams. After 12 weeks, both groups had reduced weight and waist circumference but there was no significant difference between groups. HbA1C levels were the same; they were reduced in both groups with no significant difference between groups. ^[5] The researchers concluded that fruit intake should not be restricted among type 2 diabetics.

Improving Glycemic Control With Fruits

Fructose, which is the kind of sugar found in fruits, has also been shown to actually improve glycemic control rather than be detrimental to it. In 2012, six studies were examined and revealed that small doses of fruit less than 10 grams per meal or 36 grams per day was able to improve post-prandial blood sugar levels without adverse effects on body weight or fasting insulin levels. ^[6] The researchers recommend further studies being done, particularly longitudinal studies that last more than 6 months to confirm their results.

This goes to show that fruits aren’t the problem; fructose only becomes harmful when it is refined and added to high-fructose corn syrup and table sugar – which in turn are added to unhealthy snacks and packaged food found in the market. Dr. Bistrian, a professor at Harvard, says that fruits are not harmful, and are beneficial in almost any amount – seen in the 2012 study by Sievenpiper. ^[7]

Further Benefits Of Fruit In Your Diet

Fruit (and vegetables) also have other benefits aside from improving your blood sugar control and weight loss. A diet high in fruit intake can also improve lipid levels, specifically by lowering low-density lipoprotein (LDL) levels. LDL is also called bad cholesterol because it damages the blood vessels and increases your risk for heart disease, heart attacks, and strokes. A diet that was high in fruit, vegetable and nut intake was able to reduce the risk for heart disease because of this. This very same study was also able to report major improvements in bowel movements due to the fiber content of fruits and vegetables. ^[8]

Dreher (2018) reports that fruits have a myriad of potential health benefits such as but not limited to ^[9]:

– Improved gastrointestinal health due to fruit fibers which help prevent constipation, irritable bowel syndrome, inflammatory bowel disease, and diverticular disease
– Long-term weight management
– Reduced risk for cardiovascular disease and type 2 diabetes
– Reduced risk for colorectal and lung cancers
– Reducing the severity of lung diseases
– Promoting healthy aging
– Improving psychological well-being and health and reducing the risk for depression
– Improving bone density in children and adults

In fact, Dreher warns against low fruit intake and its potential impact as a population health threat.

If you want to include more fruit in your diet (and if you’re a fan of yogurt), you can try substituting snacks with fruit and yogurt. A study in 2017 focused on the health benefits of yogurt and fruit in combination with each other and the results were very promising. The researchers reported that yogurt and fruits eaten together were able to exhibit significant prebiotic and probiotic effects. Replacing high-energy, nutrient-deficient snacks (snacks with “empty calories”) with yogurt and fruit could impact your health positively through weight loss and reduced risk for diabetes and heart disease. ^[10]

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