Drinking a beverage made from lemon juice and hot water won’t suddenly make you drop pounds, but it’s a tool that might make a difference. Lemon juice naturally contains substances that are associated with weight loss. If you include lemon pulp in the beverage, you’ll add pectin, which helps you feel full. But the most important way this drink contributes to weight loss is when it replaces other high-calorie beverages.
Lemon Juice Components Support Weight Loss
Lemon juice contains two ingredients that are associated with maintaining a healthy weight. The first constituent -- ascorbic acid, or vitamin C -- is inversely related to body mass, which means that people who consume more vitamin C weigh less than people who are low in vitamin C, according to a study in the Journal of Nutrition in 2007. When blood levels of vitamin C were tested in 118 men and women participating in the study, people who were overweight and had a larger waist measurement had significantly lower levels of vitamin C. The researchers also reported that people with adequate blood levels of vitamin C break down more fat during exercise.
Lemons are also good sources of hesperetin, which is an antioxidant flavonoid. When laboratory mice ate a high-fat diet, the animals that also consumed hesperetin gained significantly less weight than rats that did not receive the flavonoid, according to a study in Genes and Nutrition in July 2015. The researchers concluded that all rats consumed the same amount of calories, and the differences in weight were not caused by lipid oxidation; more studies are needed to verify how hesperetin affects weight and whether it has the same impact in people.
Effect of Drinking Hot Water
One small way hot water supports a diet is by keeping you hydrated. You may eat less when you’re well hydrated because thirst is sometimes perceived as hunger. Cold water requires more calories to digest than hot water, but don’t rush to replace hot water because you'll be lucky to lose an extra 8 calories with cold water. Simply drinking water uses calories to fuel digestion. Drinking 16 ounces of water increases energy expenditure by 24 percent over 60 minutes, according to a study in the Journal of Clinical Endocrinology and Metabolism in 2007.
Hot water may help you lose weight when you drink it before meals. In one study, 48 overweight adults were divided into two groups. Both groups followed a low-calorie diet, but only one group drank 16 ounces of water before each meal. After 12 weeks, the water-drinking group lost 4 more pounds than the other group, reported the scientific journal Obesity in 2010. Another study, published in the same journal in 2015, found that overweight adults who drank water before meals lost 3 pounds more than participants who didn’t drink water.
Replace Caloric Beverages With Lemon Juice and Hot Water
One of the most important ways that a lemon juice and hot water drink can help you lose weight is by using it to replace calorie-containing beverages. You can make a big dent in daily calories if you replace sugar-sweetened soft drinks. A 2-tablespoon serving of lemon juice has 7 calories. Even if you included all the pulp from a large lemon, you’d only get 24 calories, according to the U.S. Department of Agriculture. As long as you don’t add a caloric sweetener to your lemon juice and water, it’s a very-low-calorie beverage. By comparison, 1 cup of sweetened cola contains 103 calories and 24 grams of added sugar. A typical small cola from a fast-food restaurant has double the calories and sugar.
Since weight loss is achieved by consuming fewer calories than your body burns, drinking lemon juice and hot water instead of any caloric beverages you normally drink is a good place to start cutting calories without losing nutrients. A review in the May 2015 issue of the Journal of the Academy of Nutrition and Dietetics concluded that replacing sugar-sweetened beverages with water or low-calorie beverages resulted in consuming fewer calories and maintaining normal weight over time.
Pectin in Lemon Pulp Supports Weight Loss
Lemons are good sources of pectin, which is a soluble fiber that turns into a gel when it’s mixed with water. Like other soluble fibers, pectin protects your cardiovascular health by lowering cholesterol. It may also help you lose weight. As pectin absorbs moisture, it fills your stomach, which creates the sensation of feeling full and makes it easier to eat less. If you eat carbs at the same time that you consume pectin, the gel-like mass prevents spikes in blood glucose. Keeping blood sugar balanced means you don’t have extra sugar that the body will store as fat.
While pectin supports weight loss, you won't get much from plain lemon juice. An entire cup of lemon juice barely has 1 gram of fiber. Chances are you won’t use nearly that much lemon juice in a cup of hot water, which means your drink won’t contain any pectin. However, you will get pectin if you include the pulp. About 60 percent of the total weight of lemon pulp consists of pectin, according to a 1997 report in the Journal of Food Science.