Yes, desserts and high-dose fructose can be a problem for health, but really only if you have insulin resistance.
With my patients, I tend not to worry too much about sugar as long as insulin is normal on a blood test. If insulin is high on a blood test (insulin resistance), I ask my patients to avoid all desserts and dessert-type foods like dates. They can still have whole fruit.
High-dose fructose can cause or worsen insulin resistance
The problem for insulin resistance is fructose, which is the sugar in table sugar (sucrose), honey, maple syrup, dried fruit, agave, and dates. Fructose is also the sugar in whole fruit, but whole fruit is not a problem because it contains only a small amount.
It’s all about the dose. The high amount of fructose from desserts, dried fruit, or sweet drinks can cause or worsen insulin resistance because it overwhelms the small intestine’s ability to effectively metabolize and clear fructose.
Normally, the small intestine converts fructose to glucose and organic acids which can be used by the body. A high amount of fructose overwhelms the intestine’s ability to do that and so fructose reaches the microbiome and the liver where it induces oxidative stress, inflammatory cytokines, and fatty liver— all leading to insulin resistance or high insulin.
According to Princeton researcher Joshua D. Rabinowitz:
“There is a fundamental physiological difference in how smaller and larger amounts of sugar are processed in the body. And that fructose from moderate amounts of fruits will not reach the liver. You could say that the small intestine shields the liver from otherwise toxic fructose exposure.”
How much fructose is too much?
A small amount of fructose is about 30 grams per day, which is the amount from two or three pieces of whole fruit. That’s a healthy amount, even with insulin resistance.
A large amount of fructose is the 100 grams or more of added fructose from a “normal” western diet of fruit juice, granola bars, sweetened yogurts, breakfast cereals, and date balls. That’s a problematic amount, especially if there is already insulin resistance.
👉 Tip: Insulin resistance is also called pre-diabetes or metabolic syndrome. It’s a common cause of obesity and metabolic disease. Find out more: Reverse Insulin Resistance in 4 Easy Steps.
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.
Testing for insulin resistance
How do you know if you have insulin resistance?
You don’t test glucose.
Instead, you test “fasting insulin” or “glucose tolerance test with insulin.” A healthy fasting insulin is less than 8 mIU/L (55 pmol/L).
If your fasting insulin is less than 8 mIU/L (55 pmol/L), you’re fine. You can have fruit and the occasional dessert.
If your fasting insulin is higher than 8 mIU/L (55 pmol/L), you have insulin resistance. You can have whole fruit but you should strictly avoid all dessert-type foods including sweetened yogurts, smoothies, date balls, and fruit juice. At least until you revese insulin resistance.
Quitting dessert 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.
According to researcher Richard Johnson from the University of Florida:
“Starch-based foods don’t cause weight gain like sugar-based foods and don’t cause the metabolic syndrome like sugar-based foods. Potatoes, pasta, and rice may be relatively safe compared to table sugar. A fructose index may be a better way to assess the risk of carbohydrates related to obesity.”
That doesn’t mean it’s fine to eat tons of starch and nothing else. If you already have insulin resistance, too much starch could also be a problem.
The best strategy is to first eat sufficient protein, because protein will make you feel full.
👉 Tip: You need about 30 grams of protein with each meal. That’s equivalent to about one chicken breast.
After hitting your protein target, you can either:
- Quit desserts but continue to eat starch. By doing so, you will probably be able to successfully reverse your insulin resistance and insulin-resistant PCOS.
- Quit desserts and also reduce starch. By doing so, you may further improve insulin resistance but don’t do it for too long of you could lose your period. Read: Have You Lost Your Period to a Low Carb Diet?
And do not make the mistake of reducing starch but continuing to eat sugar! In other words, do not forgo potatoes with dinner only to binge later on dessert (even a so-called “healthy” dessert).