We all know this difference from the menus: Certain vegetables are considered “free,” meaning you can eat them without limitation, while fruits – even those low in sugar – are counted by portions.
But how can that be, when watermelon has only about 30 calories per 100 grams, less than carrots which have about 40 calories?
The difference is not only in the number of calories but mainly in how the body digests and absorbs the sugar.
Vegetables like carrots, peppers, tomatoes, cucumbers, and cabbage – contain few carbohydrates, lots of fiber, and cell walls that are hard to break down. All of these lead to very slow sugar absorption and a prolonged feeling of satiety. That is why they are considered “free.”
Fruits, on the other hand, even when they are low in calories, are digested quickly and absorbed faster – and therefore are treated as a separate portion.
Why is a carrot different from a watermelon?
Fibers and cell content: In carrots the fibers are thick and harder to digest, and they partially block sugar absorption.
Duration of digestion: Carrots and similar vegetables stay longer in the stomach, which prolongs the feeling of satiety.
Watermelon is soft and sweet: Although the sugar content in watermelon is relatively low compared to other fruits (about 7-8% sugar), it is eaten in very large quantities and easily, and since it is digested quickly – its sugar is absorbed rapidly.
Many times people also talk about the “glycemic index” – how quickly food raises sugar levels. But it is no less important to understand the concept of “glycemic load” – that is, the effect of a real portion.
Watermelon, for example, is considered to have a high glycemic index, but the glycemic load of a medium cup of cubes is actually low. The problem is that it is very easy to eat a huge bowl, and then the overall load jumps.
In carrots, even if the index is not very low, the actual quantity eaten and the high fiber make the effect on sugar minimal.
The simple rules
Non-starchy vegetables (carrots, peppers, cucumbers, lettuce, cabbage, and more): “Free” – can be eaten without worry.
Starchy vegetables (potatoes, corn, sweet potato): Counted like a carbohydrate.
Fruits: Even if they are low in calories, they are counted as portions. Usually, the recommendation is 1-2 fruit portions a day.
<br>How to reduce the sugar rise after fruit?
Eating fruit alone, especially when it is soft and sweet like watermelon or grapes, causes a relatively fast rise in blood sugar levels.
But if you combine the fruit with a source of protein or healthy fat – for example, natural yogurt, cottage cheese, or a handful of nuts – you get a completely different response: Digestion is slower, the sugar is absorbed gradually, and the rise in sugar levels is more moderate.
The protein and fat slow down stomach emptying and prolong digestion time, and the fibers in nuts contribute even more to stabilizing sugar levels.
A study published in the American Journal of Clinical Nutrition showed that when participants ate a meal that included carbohydrates together with protein or fat, blood sugar and insulin levels after the meal were about 20-30% lower compared to eating the carbohydrates alone.
The meaning is that such a combination not only contributes to satiety but also reduces the risk of a one-time sugar overload on the body.
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