Several readers have asked lately about the impact of fruit–specifically the sugar in fruit–and it’s capacity to cause weight gain and accelerate aging through insulin signaling:
“Do people usually gain weight because of eating fruit and does the sugar in fruit age us? I just hate to think that I am doing my body harm by eating fruit.”
If this question sounds insane to you, it shouldn’t. It is actually a very reasonable query that was sparked by two Summer Tomato articles, one about saving money while eating healthy and another on calorie restriction, aging and quality of life. In the first article I recommend thinking of fruit as dessert, a treat to be enjoyed once or twice per day. The second article is about the impact of sugar and calories on aging.
The fact is that fruit contains a lot more sugar than other natural foods and in large enough quantities it can contribute to weight gain. But fruit is certainly not bad for you, nor is it worse for your health than anything else in life.
The sugar in fruit contributes calories to your diet, but since you need calories to survive fruit is still a very good choice. The reason is that in addition to sugar (fructose, to be specific) fruit also has vitamins, minerals, antioxidants, fiber and many other things that contribute to health and possibly slow aging.
On the rare occasions when I do make an effort to lose a little weight, however, remembering that fruit should be dessert is something I keep in the back of my mind. I eat fruit every day, but when trying to lose weight I keep it under two servings and always choose whole fruit–avoiding anything blended or juiced. (Drinking calories is usually a bad idea.)
But this healthstyle tactic is not for everyone.
Unlike most people trying to lose weight, I already have a very healthy diet and fruit is one of the easiest places I can trim calories without feeling deprived. Cutting out things like fat and protein make dieting very difficult because you are always hungry. In my experience reducing unnecessary carbohydrates–especially sugars–is the easiest and healthiest way to lose weight.
But it is essential to remember most people are not overweight because they eat too much fruit and the vast majority of people would benefit from eating more of it.
The question about whether sugar causes aging is a fascinating one that I am very interested in.
Yes, in most organisms eating sugar has been shown to promote aging, but this has not been proven in humans. Sugar induces aging via the insulin signaling pathway, so therefore any food that increases insulin signaling could theoretically accelerate aging. The problem is that you need insulin to survive–those who cannot produce insulin have a disease called type 1 diabetes.
The good news is that eating a diet that minimizes insulin signaling is also the best way to lose weight and stay healthy, so if you are living a healthy lifestyle (one that includes fruit) you do not need to worry about anything else.
Although fruits have sugar, it is extremely unlikely that they accelerate aging. In fact, most evidence suggests that fruit slows aging because of its high levels of vitamins, minerals and antioxidants.
If anti-aging is your goal, fruit is your friend not your enemy.
For more on insulin signaling, check out my post at MizFit Online, When is a calorie not a calorie.
While fruits contain sugar, they do not pose a special threat to your health goals. Eat and enjoy fruits as a wonderful and delicious part of life.
How much fruit do you eat?
Originally published August 31, 2009.