Real talk: It could take weeks or months to see the metabolic effects of exercise on the scale, and even then, building muscle, which is denser than body fat, could lead to weight gain. "Do what you like because it’s good for you," Dr. Seltzer says, noting the way exercise is awesome for your heart, mental health, and more—and that not all measure of progress can be seen on the scale.
If you’ve been eating fast food for years, get real about your approach: You’re probably not going to stick to an organic, gluten-free, paleo overhaul for very long. "You want to change as little as possible to create calorie deficit," says Dr. Seltzer, who insists the best way to support sustainable weight loss is to incorporate small changes into existing habits. So instead of giving up your daily BLT bagels in favor of an egg-white wrap, try ordering your sandwich on a lighter English muffin. Or say you eat a snack bar every afternoon: Swap your 300-calorie bar for a 150-calorie alternative. "Your brain will feel the same way about it, so you won’t feel deprived," he says.