Calories are the energy in food and beverages, allowing you to move, breathe, and survive. The number of calories a person needs per day varies depending on several factors, such as age, height, ...

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. If you want to start ...

Add Yahoo as a preferred source to see more of our stories on Google. Want to lose weight? Understanding how calories actually work is key - Julia Lena Morell You may have a pretty good idea of how ...

The number of calories you need to eat to lose weight depends on several factors, including your sex, age, physical activity levels, genes, and medical history. No matter what, you need to be in a ...

You’ve heard the saying “calories in versus calories out” when it comes to weight loss. This is referring to a calorie deficit. But what is a calorie deficit, exactly? Basically, you need to take in ...

Here's how to optimize your workouts and lose weight sustainably.

This article was reviewed by Craig Primack, MD, FACP, FAAP, FOMA. You’ve heard the saying “calories in versus calories out” when it comes to weight loss. This is referring to a calorie deficit. But ...

With the emergence of smartphones, it's become easier than ever to count your calories. Whether you're trying to lose weight or simply keep track of how much you're eating, there's a simple way to do ...

Most people think of weight loss as a math problem: calories in versus calories out. In reality, your body sees it as a survival threat. When calorie intake falls or body fat decreases, biological ...

Intermittent fasting and calorie deficits can both be used for weight management and fat loss—in most cases, the most effective eating plan is one you're able to adhere to long term.