5 Experts Told Us Exactly What to Do to Burn Fat and Build Muscle, and We're Starting Tomorrow

Rondel King, MS, CSCS, an exercise physiologist at NYU Langone's Sports Performance centre, told POPSUGAR that instead of focusing on isolated exercises like a bicep curl, you should do compound exercises to burn fat and build muscle.

Compound exercises are multijoint movements that work groups of large muscles like squats and deadlifts. If you're wondering why compound exercises are better than isolated exercises for fat loss and muscle building, it's because they elicit a greater energy expenditure, which simply put means you have to work harder to perform them. As a result, you'll burn more calories and fat.

Here's a list of compound exercises you should be doing.

Compound exercises will definitely help you burn more fat and build muscle, but you should also challenge yourself with progressive overload. "Progressive overload is a gradual increase in the amount one lifts during resistance training," ACSM-certified personal trainer Jim White, RDN, owner of Jim White Fitness and Nutrition Studios told POPSUGAR.

Not only will you have to gradually increase the weights to see a change in your body composition, you'll also need to focus on the eccentric portion of the exercises you do. "Eccentric movement or exercise is really when the muscle is lengthening," Heather Milton, MS, CSCS, an exercise physiologist and clinical specialist at NYU Langone's Sports Performance Centre told POPSUGAR. For example, if you're doing a bicep curl, the eccentric part of the exercise is when you're lowering the weight back down to your thighs.

In order to build muscle with eccentric exercises, you'll need to focus on slow and controlled time under tension (this is the hypertrophy, or muscle-building phase), Heather explained. Don't forget to focus on your tempo! In the muscle-building phase, you'll need to follow a three- or four-count tempo during the eccentric portion of the exercise.

If you're not sure how heavy you should be lifting, use this simple guide.

Lifting weights is an effective way to burn fat and build muscle, but fasted cardio can also help. "Fasted cardio is exercise that increases your heart rate done in a fasted state, or in other words, done when your body is not fed and no longer processing food," Perri Halperin, MS, RD, a clinical dietitian at Mount Sinai Hospital told POPSUGAR.

When you do fasted cardio, your body uses fat as a source of energy instead of carbohydrates, Perri explained. Fasted cardio isn't better than other fat-burning ways of training like sprinting and weightlifting, "It's just different," she said. Because fasted cardio causes your blood sugar to drop, which can lead to lightheadedness and fainting, Perri said some people may want to skip it.

There is one caveat when it comes to fasted cardio: your body may use energy from muscle, which means some people may experience muscle loss. Before implementing fasted cardio into your routine, speak with your physician as it can affect metabolic conditions like diabetes.

Muscle building may sound easy, but it's actually a lot of hard work. You'll have to go hard in the gym, and you'll also need to make sure that your nutrition is on point.

Brittany Linn, RD, CDN, a clinical nutrition coordinator at The Mount Sinai Hospital told POPSUGAR that you should eat one to three hours before exercising. Go for something that's high in carbs and lower in protein (so that you can digest it quicker) like fruit with yoghurt or toast with peanut butter and some banana.

According to Brittany, you should try and eat within 30 minutes after completing a workout. She recommends consuming something that is high in protein along with carbs in order to rebuild and replenish your muscles, for example, a protein, some brown rice, and vegetables or a protein shake.

Generally speaking, you should have a good balance of all the macronutrients — carbohydrates, fats, and proteins — as protein alone won't help you build muscle.

Heavy lifting, compound exercises, and cardio will definitely tire you out, which is why it's important to do recovery work. Instead of going hard 24/7, be sure to implement yoga and stretching in your weekly workout schedule. Don't forget about getting enough sleep every night. According to the Centres for Disease Control and Prevention, adults should get a minimum of seven hours of sleep per night.

Heather explained that the tiny tears that occur while lifting weights get repaired when you sleep. So in order to improve your muscle quality, health, and strength, you've got to rest!

Here's a great yoga flow for weightlifters and expert-approved tips on how to improve your sleep.