Lemon infused water is a popular drink for weight loss, thanks to celebrity sippers like Gwyneth Paltrow and Miranda Kerr. Proponents claim that it flushes toxins from the system, reduces appetite and tweaks the body’s digestive processes in ways that block fat absorption.
Trouble is, it doesn't work like that. In fact, lemon water leaves out the most effective part of the fruit.
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The drink's hype seems to stem from a 2008 Japanese study that linked lemon's polyphenols—micronutrients with antioxidant properties—to less weight gain and improved fat metabolism in mice who were fed a high-fat diet. It’s possible, the study team said, that lemon polyphenols may stimulate the liver to produce enzymes that help block the absorption of dietary fats.
This kind of research is like rocket fuel for those looking to market a new “miracle” food. But there are a lot of problems with such optimism. The research was in mice, not people, and there have been no rigorous studies showing that sipping lemon water can promote weight loss in humans, says Dana Hunnes, a senior dietitian at the University of California, Los Angeles Medical Center.
Another problem is that lemon water uses the juice, not the rind. Mice in the study were eating a diet loaded with lemon rind, the site of most of the polyphenols in lemons. While many committed lemon-water fans may be zesting some rind into their water, it’s likely nowhere near the amount the mice in the study were consuming. (Even if you were committed to loading your diet with lemon, some research suggests that the acid in a lemon-heavy diet could seriously corrode your teeth.)
Of course, lemon is healthy in moderation. It's a good source of vitamin C, and some studies have linked low vitamin-C status to obesity. But that's a large leap from saying that ingesting more vitamin C can prevent or reverse weight gain, she says.
Pectin, a kind of fiber found in lemons, has also been linked to some weight loss benefits. “Pectin can lower LDL or bad cholesterol and has some anti-inflammatory benefits,” says Bahram Arjmandi, a professor of nutrition at Florida State University and editor-in-chief of the Journal of Food and Nutritional Disorders. “It can also prevent fat absorption and moderate insulin response.” But most pectin comes from the flesh or pith of a fruit, not its juice. You're better off eating an apple. “You’d have to eat a whole lot of lemon to see these benefits,” he says. “It’s hard for me to imagine that being practical.”
You get it by now: swigging a glass or two of lemon water will not provide much benefit. “Lemon water is not a miracle weight-loss food,” says Elizabeth Dejulius, a registered dietitian nutritionist with Cleveland Clinic.
But miracle-talk aside, lemon water could indirectly help people lose weight. For one thing, thirst is often mistaken for hunger, Dejulius says. Because many people find plain water boring or difficult to drink in large quantities, adding lemon to water may lead some people to drink more of it and stay better hydrated, thus reducing thirst-triggered food cravings. “Dehydration can also slow metabolism, which in the long-term can lead to weight gain,” she says.
Someone who swaps soda or another sugary drink for lemon water will be much better off, Hunnes says, as long as you don't sweeten it with added sugar.
Not all experts are ready to close the case on lemon water and weight loss, however. Hunnes says she found a little research linking the way lemon stimulates taste buds to appetite suppression. But there's not strong evidence yet to support that finding, she says. The power of the placebo effect could also play a role. “If your mind believes strongly that drinking lemon water does something, like suppresses appetite, maybe it will,” Arjmandi says. “This kind of placebo effect is always a possibility.”
Bottom line: If you like drinking lemon water, sip away—especially if it’s helping you skip less-healthy drinks. But if you’re looking for evidence-backed ways to lose weight, look elsewhere on your plate.