Bob Harper Shares "One of the Best Weight-Loss Tips in the World," and It's Totally Doable

Bob Harper knows a thing or two about health. As a trainer and then host of The Biggest Loser, he's helped dozens of people transform their bodies and their lives. And after suffering a heart attack last year, the fitness expert has worked on overhauling his own lifestyle, losing 40 pounds in the process.

So while Bob eats a clean, mostly plant-based diet and works out regularly, he also has a weight-loss tip that he calls "one of the best in the world." The best part? It's so easy, you can start doing it right now.

"Water intake is, I believe, one of the best weight-loss tips that you can do," Bob said in an Instagram video as part of a series he calls #TwoCupsIn. He added that if you're feeling hungry, you should drink water first. In the Instagram caption, Bob said he drinks at least a gallon of water every day and it has helped him stay energized and "regular."

Just be careful if you are exercising and sweating regularly; you will lose electrolytes in the process, so be sure to replenish with, in addition to water, some electrolytes, such as with an electrolyte-infused water or electrolyte tablets (we like Nuun Hydration Drink Tablets ($18)). There is such a thing as drinking too much water, so while a gallon (128 ounces) a day is a good amount to aim for, try not to drink too much more than that.

Shooting for about 100 ounces (12.5 cups) a day is a great place to start — if your urine is nearly clear, that means you are properly hydrated and don't need much more than that. Filling up on water instead of sugary or artificial-sweetener-laced beverages will help you feel full, keep your body hydrated, and ultimately help you lose weight.