The Truth About Fruit Sugar on a Plant-Based Diet

(This is the Third in a series of articles on the perils of added sugar. Be sure to check out the second article, “Fight Sugar Cravings with Plant-Based Nutrition”). 

My previous two articles in my series on added sugar, “12 Tips for Avoiding Sugar Cravings on a Vegan Plant-Based Diet” and “Fight Sugar Cravings with Plant-Based Nutrition,” were based on a consideration of the serious health risks posed by excessive consumption of refined sugars, such as granulated cane and beet sugar and high fructose corn syrup. But what about the naturally-occurring sugar in fruit? Is fruit sugar, also known as fructose, OK for those of us on a whole foods plant-based diet, or do we need to limit our consumption of those mouth-watering bananas, berries, oranges, cherries, peaches, apples and melons?

After all, fructose is the source of sweetness in corn syrup and fruit alike. Does it really matter for our weight and overall health where that fructose comes from? (Just for the record, granulated table sugar is composed of sucrose.)

I’ve got some good news for you, dear plant-based eaters. The answer is an unqualified, resounding “yes,” it absolutely matters where fructose comes from.

The Whole Food Advantage

According to plant-based pioneer Michael Greger, M.D., only commercially-produced fructose, not whole fruit-derived fructose, is associated with a decline in liver function and an increase in high blood pressure. In fact, a study has shown that people on a diet who ate fruit lost more weight than those on a diet that restricted all fructose. Another study demonstrated that people who ate berries along with refined sugar, despite the fact that the berries raised the total amount of sugar consumed, didn’t suffer from blood sugar spikes and the resulting hypoglycemia from a spike in insulin production that would be expected when consuming just refined sugars.

(Insulin is an important hormone produced by the pancreas that allows your body to use or store the sugar it consumes and regulates the amount of glucose in your bloodstream to prevent both too little blood sugar, or a condition known as hypoglycemia, or too much blood sugar, which is called hyperglycemia.)

Randomized controlled trials have shown that eating fruit reduces oxidative stress markers and blood glucose in diabetics. And reducing fruit consumption has been shown to have no effect on blood sugar, weight loss, or waist circumference.

What does all this science mean for you? Go ahead and enjoy that fresh fruit salad!

Whole Fruit Versus Juices and Dried Fruit

Dr. David Ludwig, in a 2013 article in the Journal of the American Medical Association, said that there’s utterly zero risk that accompanies the consumption of even unlimited amounts of whole fruit. In fact, Ludwig cited studies which show that increased fruit consumption is associated with lower, not increased, body weight and a corresponding decreased risk of obesity-related diseases, such as diabetes and heart disease

The sugar in fruit is contained within the cells. It’s the fiber in fruit, Ludwig said in a New York Times article, that slows the breakdown of the fruit’s cell walls, thereby slowing down the digestion and assimilation of ingested whole fruit-derived fructose into the body. It’s best when the cell walls of the fruit remain intact, so the health benefits of whole fruit would not necessarily apply to fresh juicing and commercially-produced fruit juices or juice drinks, for those of you wondering.

Juices with the fiber removed, such as most commercially-produced juices, are the most concerning. If you’re juicing, it’s better to blend the fruit juice with the fiber in a blender, rather than juice it with a juicer designed to remove the fiber, but neither fruity liquid offers the benefits of whole fruit. It’s the intact cell walls in fruit that give the liver more time to metabolize the sugar that you’ve eaten, which reduces the risk of blood sugar spikes and the associated stresses on the pancreas from excessive insulin production that can lead to diabetes.

In fact, in the same NYT article, all three medical experts cited advised against juicing. The necessity of chewing fruit slows us down when we eat it whole, versus the way we might guzzle down a glass of fruit juice sending sugar into our systems much more quickly. Dr. David Katz is quoted saying that while dried fruit concentrates sugar and calories, making it easier to overeat, it contains an intact cellular structure and all the benefits of fruity fiber, making it second only to whole fruit.
Other Benefits of the Fiber in Whole Fruit

The fiber, and water, in fruit can also help create a feeling of satiety, or fullness. The fiber in fruit slows down its digestion and means that the fruit travels considerably further down the intestines, where the satiety hormones leptin and ghrelin that shape our appetite and hunger signals, tend to hang out. Processed foods, on the other hand, are typically digested in the first few feet of the intestinal tract.

So, in other words, the same grams of sugar in a soft drink versus an apple or orange will have a radically different effect on your body. What that means is that all “grams” of sugar are most definitely not created equal, you can’t just look at the quantity of sugar that a food or beverage to know how benign or detrimental it will be to your health.

Another benefit of fiber, whether it’s from lettuce, brown rice, carrots, beans or yes, whole fruit, is that it may contribute to a healthy gut microbiome. Fiber may be indigestible to humans, but the hundreds of species of good bacteria in our intestinal tract feed on it, which helps us maintain a healthy immune system. Researchers are finding connections between gut microbiome health and an increasing number of health conditions, such as stroke, dementia, cardiovascular disease and autism. And did you know that eating a high-fiber diet is correlated with an overall lower mortality rate? That’s right! Eat fruit, live longer. Sounds like a plan to me!
Nature Knows Best

It’s smart to be concerned about the very real dangers of added, refined sugars. But when it comes to nature’s dessert, whole fruit, go ahead and enjoy yourself! Your body, and your waistline, will love you for it.

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