Whether you want to add muscle mass or simply look a little less like a string bean, gaining weight can be just as much of a challenge for some people as losing weight is for others. Maintaining a healthy diet while simultaneously beefing up the numbers on the scale requires a lot of hard work.

“For people trying to gain weight, it’s not [always] fun. And if you want to gain healthfully, it’s not about eating ice cream sundaes and chocolate and six slices of pizza,” says Marjorie Cohn, a Registered Dietician and the author of Belly Fat Fix and co-author of Overcoming Binge Eating For DUMMIES.

While unhealthy foods pack a lot of calories, loading up on junk could cause high cholesterol in the long run, and will only succeed in helping you gain fat — not lean muscle. To add mass and still look good, you’ll need to chow down on a combination of protein, carbohydrates and healthy fats. If you want to bump up the number you see on the scale, here’s how to go about it.

Inch by Inch: Tips for Healthy Weight Gain

Gaining healthy weight can help you tone up your biceps, improve your strength or just look that-much-better in your jeans. Follow these easy rules to put on the pounds painlessly. Before you begin, consider consulting a nutritionist to help you set realistic goals for your gain.

1. Track your calories.

The first step: figuring out how many calories you consume each day simply to maintain your weight.

“Most women would maintain weight at about 1,800 to 2,000 calories per day depending on how active they are, and most men would maintain weight at 2,500,” Elisabetta Politi, a Registered Dietician and the Nutrition Director at the Duke Diet and Fitness Center at Duke University, says.

Use a calorie-tracking tool, to figure out how much you consume normally. Then, by increasing calorie intake by 200 to 500 calories per day, you can achieve a healthy weight gain of a quarter pound to a pound each week, according to Politi.

2. Eat a balanced diet.

To ensure your extra curves are made of muscle, not fat, you’ll need to eat well-rounded meals and snacks, stacked with healthy foods and low on empty calories.

Politi advises eating 50 to 60 percent of your daily calories from carbohydrates, 15 to 20 percent from protein and 25 to 30 percent from healthy fats, such as avocado, healthy oils and nuts. While protein is often considered good for getting toned, it’s important not to go overboard when trying to gain weight, because it tends to be very filling and also requires a lot of energy to digest.

Instead, focus on “healthy complex carbs like rice, whole wheat or whole grain cereals and potatoes,” Cohn says. “We digest carbs a lot easier, so those calories can be used for muscle building.”

3. Sneak in healthy fats.

Heart-healthy olive oils, canola oils or a medium-chain triglyceride oil, like coconut oil, are your new best friends when trying to gain weight. Why? Adding them to a salad,smoothie or serving of grains can up the calories in your dish without making you feel more full.

“If you’re making rice, grains, couscous, or anything that will absorb liquid, add a generous amount of healthy fat to it, such as olive oil or canola oil, because the starch is going to absorb it,” Cohn says.

Additionally, you should stock up on a variety of nuts to snack on throughout the day. Just a handful of walnuts can pack more than 200 calories. “Nuts are great because nuts are very high-calorie, but they have a heart-healthy kind of fat,” Politi says.

What to Avoid When Putting on Pounds

While chronic dieters may find it difficult to believe that it can be hard to put on weight, gaining can be just as difficult as losing. Here’s how to overcome the challenges that may derail your anti-diet.

Pitfall #1: You’re sick of food.

Having the freedom to eat unlimited amounts of food may seem like a dream come true to some, but forcing yourself to eat beyond what you would normally consume can become burdensome.

“I actually encourage a lot of shakes,” Cohn says, noting that a simple protein shake, enhanced with healthy oils, such as coconut oil, can allow you to slowly sip your way to an extra 500 calories a day.

High-calorie drinks, such as milk or chocolate milk, can also help you reach your goal — especially if you’re looking to put on muscle.

“Milk is a very healthy beverage, and for someone who wants to build muscle, it has been found to have the correct ratio of protein to carbs, especially chocolate milk,” Politi says.

Pitfall #2: You’re uncomfortably full.

Eating when you’re already feeling stuffed can be downright painful. To avoid that I-ate-too-much stomachache, Politi recommends eating five smaller meals throughout the day, rather than three mega-sized servings.

Structuring small meals around workouts, when you’re burning the most calories, may also help you avoid feeling overly stuffed. “I definitely recommend carbohydrates before exercise sessions,” Politi says, which will help fuel your routine.

Pitfall #3: You’re cramming in all your calories at once.

If at the end of the day, you realize you just haven’t eaten enough, it may be tempting to splurge on a giant sundae or French fries. But loading up on bad-for-you foods just to meet your calorie goal may not be worth it in the long run.

“It’s not promoting muscle gain,” Cohn says, noting that consuming unhealthy foods will cause you to gain fat rather than get toned.

Weight gain derived from unhealthy foods will end up exactly where you don’t want it. For men, that means extra weight in the waist area (hello, beer gut). And if women overdo it with unhealthy foods, they’ll likely see it in their hips or stomach, Cohn says.

Resist the urge to splurge and instead focus on planning meals ahead of time in the future to avoid accidentally eating too little.

Similarly to weight loss, weight gain may require lifelong maintenance once you’ve reached your goal. By filling yourself with nutritious foods, you’ll ensure that the extra calories you’re consuming will keep you healthier than ever.

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