September 25, 2024
Green tea has been bandied about as a diet hack for centuries: In ancient China 2,000 years ago, people touted the beverage as a weight loss tool. In modern times, the drink if often mentioned in diet books and meal plans, reports The New York Times.
Now, green tea has followed the inevitable trajectory of any weight loss trick: It’s getting big on TikTok. Viral videos claim the drink aids with shedding pounds, going so far as to call it “nature’s Ozempic.” Some posts suggest drinking as many as five cups a day.
While there is some research into green tea and weight, the evidence on whether a mug (or several) can melt away pounds is unclear, said Dr. Jyotsna Ghosh, an obesity medicine doctor at Johns Hopkins University.
Many of the TikTok videos claim that green tea boosts the production of glucagon-like peptide-1 (GLP-1), a gut hormone that prompts the pancreas to release insulin after a meal. That insulin, in turn, lowers blood sugar. GLP-1 also slows down the rate at which food leaves the stomach, and it affects areas of the brain that regulate hunger.
Ozempic and drugs like it deliver a compound that mimics GLP-1, making people feel fuller faster. Many stop experiencing strong cravings for food.
Some researchers have theorized that green tea might stimulate GLP-1, in part because studies have found green tea extract can lower blood sugar in diabetic mice. But there have been only a few small studies in humans, and the results are inconclusive. One of the few clinical trials on the subject—which looked at 92 people with Type 2 diabetes—suggested there was not a notable difference in GLP-1 production between people who took green tea extract and those who took a placebo pill.
Any effect green tea might have on GLP-1 is likely to be small, experts said. Any food or drink can increase GLP-1 levels slightly, Dr. Ghosh says. But GLP-1 levels in the bloodstream dip minutes after you eat or drink something; that’s one of the reasons we get hungry again—and why temporarily boosting the hormone does not guarantee weight loss.
Ozempic and similar drugs, by contrast, linger in the body for days, and are far more potent than the natural hormone; which makes them uniquely good at suppressing appetite.
Many of the claims about green tea and weight loss mention two components of the drink: caffeine and antioxidants. Caffeine might, in theory, slightly speed up someone’s metabolism. But it is unlikely that effect would translate directly into substantial weight loss, Dr. Ghosh notes.
Green tea also contains compounds called polyphenols, antioxidants that can help protect cells from damage and reduce inflammation. Studies in animals and in human cells have suggested that these compounds could improve metabolism and reduce fat absorption from the gut. But trials in humans have had mixed results.
People turning to green tea to lose weight “can’t expect a big effect, and certainly nothing close to medications like Ozempic,” says Rob van Dam, a professor of exercise and nutrition sciences at the Milken Institute School of Public Health at George Washington University.
Julia Zumpano, a registered dietitian at the Cleveland Clinic, says that focusing on a single food or drink ignored the many other factors that played a role in weight loss. Those include a person’s broader diet, exercise habits, genetics, stress, metabolic health and even the quality of sleep an individual gets.
“Look at how you can improve lifestyle, if weight loss is your goal,” she said. “Not just specifically one food, drug, supplement, whatever it might be.”
Research contact: @nytimes
