Fruits and vegetables are healthy foods that we must include in our daily diet. In fact, experts recommend eating at least five servings a day because frequent consumption is related to a lower risk of developing diseases or dying prematurely. However, often drinking fruit juices, even natural ones, is not the most advisable, and now a new study has found that drinking a glass or more of 100% fruit juice each day is related to a small weight gain in children and adults.
The research has been carried out by researchers from the University of Toronto and the TH Chan School of Public Health at Harvard University, who have reviewed 42 studies: 25 in adults with a total of 268,095 participants and 17 in children (45,851). Their results have been published in JAMA Network and show a relationship between drinking a serving of fruit juice daily and increasing body mass index (BMI) in children. But it has also found weight gains in adults
The authors have pointed out that the problem is the amount of fruit that is ingested at one time when taken in juice form. “For example, how often do we eat three oranges? However, a glass of orange juice is approximately equivalent to three oranges that can be consumed in one or two minutes, and we can go back and drink another, and that will provide a lot of calories and cause an increase in blood glucose,” he explained. Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard TH Chan School of Public Health and professor of medicine at Harvard Medical School in Boston in an email obtained by CNN Health.
Association between fruit juice intake and increased BMI in children
The authors decided to find out the association between 100% fruit juice intake and body weight in children and adults. “Concerns have been raised that frequent consumption of 100% fruit juice may promote weight gain,” they note in the work. “Current evidence on fruit juice and weight gain has yielded conflicting results, both from observational studies and clinical trials,” they add.
They tracked the scientific evidence available in databases such as Medline, Embase and Cochrane, in studies published until May 18, 2023, and subsequently carried out a systematic review and meta-analysis of a total of 42 studies to evaluate the impact of consuming fruit juices in the children and adults who participated in them. They assessed change in BMI (calculated as weight in kilograms divided by height in meters squared) in children and change in body weight in adults.
“Our findings support guidance to limit fruit juice consumption to prevent excessive calorie intake and weight gain.”
As a result of their analysis, they found a “positive and significant” association between the intake of 100% fruit juice and an increase in BMI in children. Each additional serving per day of 100% fruit juice was associated with a 0.03 (95% CI, 0.01-0.05) greater change in BMI. In adults they also observed a positive correlation between juice consumption and an increase in body weight, but in this case the result is more variable. Studies that did not adjust for energy (calorie) intake showed an increase in body weight of 0.21 kg (95% CI, 0.15-0.27 kg).
In certain circumstances they found that people who consume fruit juices daily can gain an average of up to five kilos per year, although in other cases no such increase was found. The authors of the study have pointed out that many of the studies that have been carried out so far to discover the impact of fruit juices on the health of the population have been biased by “serious conflicts of interest” on the part of the food industry.
And they conclude: “Our findings support guidance to limit fruit juice consumption to prevent excessive calorie intake and weight gain.” Although they also recognize that it is advisable to perform additional tests in relation to the intake of 100% fruit juice and body weight.
