If you have normal insulin sensitivity and enjoy fresh fruit, then please keep doing what you’re doing. You don’t need this post.
If on the other hand, you have insulin resistance or PCOS or acne, then you will benefit from dramatically reducing desserts. Here’s what you need to know.
The problem is too much fructose
Fructose is the sugar in table sugar, honey, maple syrup, dates, agave, and high-fructose corn syrup. Yes, it’s also the sugar in fruit, and of course, fruit is healthy. We’ll come to that.
Glucose is the other sugar in table sugar and other foods. In excess, it’s not great either, but it’s not as harmful as high-dose fructose.
Exactly why is fructose so bad? Because above a certain amount, fructose induces insulin resistance, and it does so quickly, within just a couple of months. Below a certain amount, fructose does the opposite—it improves insulin sensitivity.
In other words, some fructose is fine and even healthy. That’s why whole fruit is healthy. Too much fructose causes insulin resistance and disease. That’s why fruit juice and soft drinks are not healthy.
Tip: Fructose has a relatively low glycemic index (GI), so it used to be considered the “healthy” sugar. Fructose does not spike insulin as much as glucose but it directly impairs insulin sensitivity in the liver.
Tip: Insulin resistance is a common condition of excess insulin. The only way to know if you have it is to test insulin (not glucose). For more information, please read Reverse Insulin Resistance in 4 Easy Steps.
For a fascinating historical account of how sugar causes disease, please read Gary Taube’s The Case Against Sugar.
How much fructose is too much?
How much fructose can you safely have? That is the big question, and it very much depends on you and your health. If you have normal insulin sensitivity, you can get away with a moderate intake of fructose. If you have insulin resistance, you can tolerate a lot less, and you need to reduce it, at least until you reverse insulin resistance.
A small amount of fructose is about 30 grams per day, which is what you get from two or three pieces of whole fruit. That should be fine for most of you, even if you have insulin resistance.
A large amount of fructose is the 100 grams or more that you get from a “normal” western diet of fruit juice, granola bars, sweetened yogurts, breakfast cereals, and date balls. Natural sugars are still sugar. Dates, for example, are among the sugariest foods you can eat.
Tip: Need a quick way to know if a food has too much sugar? Ask yourself: “Does it taste really sweet?” If it does—if it is essentially dessert—then it has too much fructose.
A large amount of fructose can cause or worsen insulin resistance. If you already have insulin resistance, then reducing fructose is the only way to reverse it.
What I do with my patients
When I suspect insulin resistance, I order the blood test “fasting insulin” or “glucose tolerance test with insulin”.
If a patient does not have insulin resistance, then I say it’s okay to have fresh fruit and a dessert-type food once or twice per week.
If a patient does have insulin resistance, then I say it’s okay to have two servings of fresh fruit but I ask her to strictly avoid all dessert-type foods including sweetened yogurts, smoothies, date balls, and fruit juice. We then retest insulin a few months later and discuss the reintroduction of occasional dessert-type foods.
Quitting sugar is not the same as going low carb
Sugar is a carb, so what about other carbs such as rice and potatoes? Aren’t they just as bad? In a word: No. Most starches contain mostly glucose and very little fructose. Starch does not impair insulin sensitivity as profoundly as does fructose.
That doesn’t mean it’s fine to eat tons of starch and nothing else. Over time, that could also cause insulin resistance.
And if you already have insulin resistance, you may benefit from temporarily also reducing starch. BUT, only after you’ve first reduced fructose.
Quitting sugar does NOT mean going low carb.
So there are two strategies that work:
- Quit sugar but continue to eat starch. By doing so, you will probably be able to successfully reverse your insulin resistance and insulin-resistant PCOS.
- Quit sugar and also reduce starch. By doing so, you may further improve insulin resistance. A low carb diet can feel good in the short term, but take care in the long term because it can do harm. Please read: Have You Lost Your Period to a Low Carb Diet?
There’s also one deeply flawed strategy that will NOT work:
- Reduce starch but continue to eat sugar. By doing so, you will feel terrible and not gain anything at all. My simple plea is this: “Please don’t forgo potatoes with dinner only to binge on Paleo ice cream for dessert.” Please read: Sugar Is the Worst Carb. Reclaiming the No-Dessert Diet.
What is your experience with sugar? I’d love to hear from you.
Yours in health,