While it is widely believed that consuming sugar, particularly fructose, can cause weight gain and harm our health, a recent study suggests that the quality of fructose in different foods may vary. In fact, good fructose not only aids in weight loss but also leads to improvements in other health indicators.

Fructose is more lipogenic (promotes fat production) than glucose. Excessive fructose intake is widely believed to be associated with obesity, fatty liver disease, cardiovascular diseases, and even cancer.

This is partly because fructose is primarily metabolized in the liver and converted into fat. Specifically, fructose promotes fat production in the liver and damages mitochondria (the powerhouse of the cells) and associated enzymes. Additionally, the byproducts of fructose digestion by gut bacteria further stimulate and enhance the liver’s ability to produce fat.

Fructose reduces the body’s energy expenditure, promotes leptin resistance, and stimulates appetite.

Excessive intake of fructose can lead to an increase in the intestine’s surface area, which further accelerates the absorption of nutrients and the process of obesity.

That being said, people’s understanding of fructose is not entirely accurate.

Researchers from the University of Toronto published a systematic review and meta-analysis in the American Journal of Clinical Nutrition. They examined 169 clinical trials to determine the varying effects of fructose from various food sources on human health.

The study included 14 types of fructose-containing foods:

The researchers primarily focused on body weight, followed by secondary indicators such as body mass index (BMI), to evaluate the effects of fructose on the body.

These fructose-containing foods exhibit clear trends and patterns in their effects on the body.

In the study, when fructose-containing foods were replaced with drinks containing added nutritive (caloric) sweeteners or mixed sources with sugar-sweetened beverages, the average weight gain was 0.66 kilograms and 0.27 kilograms, respectively. These findings may not be surprising to many.

On the other hand, replacing fructose-containing foods with fruit resulted in an average weight loss of 0.38 kilograms. This confirms that fruit can aid in weight loss, although the researchers note that the fruits mainly consisted of berries, such as strawberries, blueberries, and raspberries.

It is unsurprising that adding fructose-containing foods to one’s diet, such as sugar-sweetened beverages, resulted in a significant weight gain of 0.49 kilograms. Consumption of a 355 milliliter can of such beverage, which accounted for 8 percent of daily energy intake, led to an even more substantial weight gain of 1.04 kilograms. Similarly, juice drinks were found to be detrimental, resulting in a significant weight gain of 0.9 kilograms.

However, it is worth noting that 100 percent fruit juice, despite being a sweet liquid, has a fundamentally different effect on the body than sugar-sweetened beverages.

Consuming 100 percent fruit juice in moderation, with calories not exceeding 10 percent of daily energy intake, can lead to a significant weight loss of 1.30 kilograms. However, when consumed in higher amounts, weight gain may occur, albeit the magnitude of the increase is not substantial. In other words, moderate consumption of pure fruit juice can aid in weight loss, while excessive consumption may result in weight gain.

Eating fruit offers similar benefits: When consumed in an amount that does not exceed 10 percent of daily energy intake, body weight can be significantly reduced by 0.6 kilograms. However, there is no weight loss effect when it is consumed in excess. It is worth noting that both fresh and dried fruits can lead to significant weight loss, with dried fruits resulting in a weight loss of up to 1.29 kilograms.

“Most people don’t eat enough of all forms of fruit,” noted lead author Laura Chiavaroli, who holds a doctorate in nutritional sciences and is an assistant professor at the University of Toronto, in a press release.

The study also answered a question: Does consuming honey, a food mostly made up of sugar, contribute to weight gain? The answer is no.

Replacing foods containing fructose with honey resulted in the most significant weight loss among all food sources, with a reduction of 1.65 kilograms.

“More specific guidelines regarding added sugars may be needed for different food sources of fructose-containing sugars. Ultimately, calories count, as does the food source of sugars,” said John Sievenpiper, a professor in the Department of Nutritional Sciences at the University of Toronto and an author of the study.

Fruits aid in weight loss and promote a leaner body composition. The consumption of foods containing “good fructose” can lead to a reduction in body mass index (BMI).

In substitution trials, fruit led to a significant reduction of 0.21 kg/m² in body mass index (BMI).

Moderate fruit juice consumption also led to a significant reduction of 0.52 kg/m² in BMI.

The impact of dried fruits on reducing BMI is surprising. When consumed in an amount equivalent to 5.5 percent of daily total energy intake, dried fruits led to a significant reduction of 4.58 kg/m² in BMI.

While fruits, fruit juice, dried fruits, and honey have been shown to aid in weight loss, the amount consumed is crucial, as overconsumption may lead to adverse effects.

Researchers recommend consuming 50 grams or less than 10 percent of the daily total energy intake for fruits. The fruits in the study were generally low-calorie berries with high-antioxidant content.

The recommended daily intake of honey is similar to that of fruits.

The study emphasized the benefits of consuming 100 percent fruit juice, with the recommended amount being no more than 10 percent of daily total energy intake. To put this into perspective, the study mentions 125 milliliters of fruit juice, which provides 3 percent of the daily energy intake. Therefore, the amount of juice that would provide 10 percent of daily total energy intake is approximately 400 milliliters, equivalent to a medium-sized coffee.

For dried fruits that have been proven effective in reducing body weight and BMI, consuming 60 milliliters or less per day is recommended, which is roughly the amount that can fit in the palm of your hand.