Can fruit juice make you gain weight? New data from scientists
Natural, freshly squeezed juices are considered a source of vitamins and minerals and are associated with a healthy lifestyle. However, they can be a serious hindrance to your slimness, experts warn.
According to a new research analysis, there is a link between daily fruit juice consumption and extra pounds in children and adults. Why can natural juice cause weight gain? How is it safe to consume your favorite beverages? And why is fruit better to eat rather than "drink"?
Too caloric and high in sugar: what are the dangers of juices?
Drinking more than 1 cup of 100% fruit juice per day has been linked to weight gain in children and adults, according to a new review that analyzed 42 studies .
"One of the fundamental problems with juicing is the quantity; drinking fruit in this way leads to overdose," states leading nutrition researcher Walter Willett, professor of medicine at Harvard Medical School.
"For example, how often do we eat three oranges? However, a glass of orange juice is about three oranges that can be 'eaten' in 1-2 minutes. We can then go back and drink more, which will add even more calories and cause our blood glucose levels to spike," notes Dr. Willett.
Experts say that over time, high blood sugar levels can lead to insulin resistance, metabolic syndrome, diabetes, heart disease, obesity and other chronic diseases.
Because of concerns about rising rates of childhood obesity and tooth decay, the American Academy of Pediatrics AAP advises parents to avoid juice completely for children under 1 year of age. For children ages 1 to 3, experts recommend limiting juice intake to 120 ml per day, and for those ages 4 to 6, at least 170 ml per day.
Better to eat: why are whole fruits and vegetables healthier than juice?
Tamara Hannon, a pediatric endocrinologist and member of the American Academy of Pediatrics nutrition committee, who was not involved in the study, believes the research is credible and consistent with clinical observations by pediatricians.
"There's really no health reason to consume juice instead of whole fruits and vegetables unless your child can't tolerate eating regular foods," Hannon says.
According to U.S. national nutrition guidelines, teens and adults should drink no more than 240 mL of natural juice per day. That said, the drink should not be considered a healthy way to quench thirst.
"The general recommendations are against the 'routine' consumption of juice instead of water when quenching thirst. Juice should be consumed occasionally as a healthy product," emphasizes Dr. David Katz, a specialist in preventive and lifestyle medicine. The expert also notes that fruit juice is better than sodas, but should be consumed occasionally for pleasure.
How does juice affect the body?
Speaking about the dangers of fruit juices, one can mistakenly come to the conclusion that fruit is also harmful, but this is not true. There is a difference between a fruit and its juice - our bodies digest these products differently," experts say.
"Whole fruits and vegetables consist of a set of nutrients - carbohydrates, proteins, fats, minerals and vitamins, which are contained in fiber. It is in this form that we should consume them," states Dr. Hannon.
Juice lacks the fiber and structural parts of the product, so our bodies digest and assimilate it differently than they have evolved to do so, adds the expert.
For example, eating a whole apple does not lead to an increase in blood sugar levels. This is because fructose and sugar, which are found in fruits and in some vegetables, slowly enter the bloodstream. Whereas drinking apple juice fills the bloodstream with fructose.
"The blood can't be sweet. It's dangerous for the organs, so there are many mechanisms in the body to get rid of sugar quickly and maintain normal blood sugar levels," Hannon explains. "For example, the liver, which metabolizes sugars, turns those calories into fat to keep them out of the bloodstream," adds the doctor.
Portion size matters
The new meta-analysis includes 42 studies, 17 on children and 25 on adults. "Meta-analyses are good because they combine data from smaller studies so they can be analyzed as if they were one large study," says Hannon.
According to the study, each additional serving of fruit juice per day was associated with a 0.03 increase in body mass index in children and a 0.02 increase in body mass index in adults. These findings seem insignificant only at first glance.
"Considering that most people do not drink the standard 120-150 ml serving of juice, but consume 3-4 times more per day, this is what leads to a significant increase in BMI. My advice to parents: don't think of juice as a healthy drink when you are thirsty," notes Hannon.
Pediatricians and healthy eating experts recommend that parents offer whole fruit, not juice, to their child as a snack. Neither fruit nor vegetable juices should be drank in place of water because they are high in calories and sugars that enter the bloodstream too quickly, unlike whole foods. Fans of natural, freshly squeezed juices are recommended to consume no more than half a glass of the drink per day.