Fruit Restriction for Type 2’s: Good or Not?

Danish hospital researchers show that the recommendation among conventional doctors and nutritionists to type 2 diabetes patients to lay off the fruit may be wrong…. 

The researchers tested fruit consumption on 63 men and women who had been recently diagnosed with type 2 diabetes. The researchers randomized the participants into two groups. One group was given the advice to eat at least two fruits a day, while the other was given the more common conventional medicine advice to eat no more than two fruits a day. This advice accompanied the other typical medical and nutritional advice typically given to diabetics.

The participants then recorded their fruit consumption each day for three months. Before and after the trial began the patients were tested for HbA1c status, body weight and waist circumference. Because many of the patients were overweight, their diet plan also included strategies for weight loss. The patients studied all had HbA1c’s over 6.5%.

After the three months on their new diets, the patients were all re-tested, and their fruit consumption was analyzed together with their HbA1c results, weight and waist size.

The researchers found that those on the high fruit diet had little difference in their relative HbA1c levels, amount of weight loss or waist size as compared to the group that consumed less fruit.

The researchers concluded that, "A recommendation to reduce fruit intake as part of standard medical nutrition therapy in overweight patients with newly diagnosed type 2 diabetes resulted in eating less fruit. It [consuming less fruit] had however no effect on HbA1c, weight loss or waist circumference. We recommend that the intake of fruit should not be restricted in patients with type 2 diabetes."

In fact, when the data is looked at more closely, those who ate more fruit had slightly more weight loss and lower ending waist circumference than those who ate less fruit.

The high-fruit diet group had an average weight reduction of 2.5 kilos while the low-fruit diet group had a 1.7 kilogram average loss in weight. Meanwhile, the high-fruit diet group had an average waistline shrinkage of 4.3 centimeters, while the low-fruit diet had an average shrinkage of 3.0 centimeters.

One reason why this nutritional advice of lower fruit consumption could be erroneous is that conventional medicine does not always take into account the importance of fiber within fruits. Whole fruits contain a number of long-chain polysaccharides such as pectin which have been shown to reduce glycemic levels and balance blood sugar.

Research at the Veterans Affairs Medical Center in Minneapolis in the early 1990’s — published in the Journal of the American College of Nutrition — tested seven diabetic men with bananas of various ripeness. Their testing illustrated that the ripeness of the bananas had no effects upon the patients’ levels of glucose, insulin, C-peptide and glucagon.

Just about every whole fruit will contain both soluble and insoluble fiber, often at optimum levels for our digestive tract. Fiber levels among fruits range from a low of about three grams for every 100 calories to a high of seven to over eight grams per 100 calories – among raspberries, blackberries (about a cup), prunes and figs. An apple or pear will contain close to four grams each. (Fruit juices, on the other hand, present the sugar of fruits without their fiber. Thus fruit juices are a quite different thing altogether.)

Most health-oriented nutritionists suggest that between 30 and 40 grams a day of fiber is best, while some suggest as low as 25 is okay. Most Americans eat between 10 and 15 grams per day. Fiber is critical to maintaining blood sugar balance.

Soluble fiber – also called water-soluble – has been shown to lower cholesterol because it prevents bile from reabsorption – as bile acids are produced from cholesterol. Fiber will attack bile acids and escort them out of the body. Soluble fiber also slows carbohydrate absorption and decreases insulin requirements. These together help balance blood sugar levels. Insoluble fiber attaches to toxins and waste material in the digestive tract and escorts them out of the intestines.

Fruits make up one of the best ways to get both soluble and insoluble fiber. Other ways include whole grains and seeds.

Christensen AS, Viggers L, Hasselström K, Gregersen S. Effect of fruit restriction on glycemic control in patients with type 2 diabetes–a randomized trial. Nutr J. 2013 Mar 5;12:29.

Ercan N, Nuttall FQ, Gannon MC, Lane JT, Burmeister LA, Westphal SA. Plasma glucose and insulin responses to bananas of varying ripeness in persons with noninsulin-dependent diabetes mellitus. J Am Coll Nutr. 1993 Dec;12(6):703-9.