Browse evidence-based analysis of health-related claims and assertions
Drinking a large glass of water on an empty stomach can make your body burn a few extra calories, especially if you're overweight, because it tricks your cells into thinking they're hydrated and need to work harder.
Correlational
If you drink water instead of soda, juice, or milk with your meal, you tend to eat less food overall, which can help you take in fewer calories.
This study only looked at young women — so we can’t say if drinking more water helps men, older people, or those who are severely obese.
Descriptive
Even though the study says water makes your body burn more calories, it didn’t actually measure whether that happened — so that part of the claim is just guessing.
Mechanistic
Overweight young women who drink more water for two months tend to have a slightly lower BMI, even if they didn’t change what they ate.
Drinking a large glass of water before each meal for two months is linked to a small but measurable drop in body fat measurements at the arm, belly, and thigh in overweight young women.
When young women who are overweight drink an extra six glasses of water a day before meals for two months, they tend to lose a little weight, their BMI goes down a bit, and their body fat measurements slightly improve.
Cooking nuts and other fatty foods may have helped early humans grow bigger brains and be more active because it gave them more energy from the same food — like getting a free energy boost.
Nutrition labels say raw and roasted peanuts have the same calories, but your body actually gets more energy from roasted ones — the current system doesn’t account for how cooking changes how well your body can digest the fat.
Quantitative
Cooking peanuts breaks open the tiny protective shells around the fat inside, making it easier for your body’s digestive juices to reach and break down the fat.
Crushing peanuts into butter doesn’t help your body get more energy from them — only cooking does. Mice that ate blended peanuts gained the same amount of weight as those that ate whole ones, even though the nuts were crushed.
When you cook peanuts, your body can absorb more of the fat inside them, so you get more energy from the same amount of peanuts — mice that ate cooked peanuts gained more weight than those that ate raw ones, even when they ate the same amount.
When you eat protein before a bike ride, your heart beats faster than if you hadn’t eaten — but you don’t feel like you’re working harder, and you still ride just as hard.
Causal
Whether you eat carbs, protein, or nothing before a bike ride, you don’t feel hungrier during or after the ride — your appetite stays about the same.
Eating protein before a hard bike ride doesn’t make your body produce more harmful stress molecules than eating carbs or riding on an empty stomach — your cells aren’t more damaged.
Whether you eat carbs, protein, or nothing before a hard cycling workout with short bursts of maximum effort, your power output stays the same — your body can still push hard regardless of what you ate beforehand.
If you're a trained cyclist and want to burn more fat during a moderate ride, eating a protein snack before you start works just as well as riding on an empty stomach — but eating carbs before you ride cuts down on fat burning.
These diets can sometimes cause dangerously low blood sugar or dangerous acid buildup in the blood, so they should be done with a doctor’s guidance.
The more you move each week while dieting, the more fat you tend to lose, even if you’re eating the same amount.
Combining keto diet with skipping meals two days a week helps overweight people lose more fat and weight than doing either one alone.
Skipping food two days a week (but not starving) for 3 months helps overweight people lose a bit of fat and weight, on average about 3.5% body fat and 2.8 kg.
Eating mostly fats and very few carbs for 3 months helps overweight people lose fat and weight, on average about 5% body fat and 3.5 kg.
After losing weight, whether you eat low-carb, medium-carb, or high-carb doesn’t change how much you move around — people stay just as active no matter what diet they’re on.
After losing weight, people on low-carb diets have less of the fullness hormone leptin than those on high-carb diets, which might make them feel less full.