If you want to gain weight and build muscle, you’ve got to eat more calories than you’re expending.1 There’s no way around it. And if you’re a naturally skinny guy who can’t gain weight no matter how much you think you’re eating, you’ve got to eat more, period. 
The reason you find it hard to gain weight is quite simple: you’re a NEAT freak. Your non-exercise activity thermogenesis2 - or the number of calories you burn from day to day activity (brushing your teeth, tossing and turning in bed, etc.) – is high, so you require more calories than the majority of people. 
But fear not. Today I am going to share several simple strategies to increase your appetite so you can eat enough to gain size without dinner feeling like a Chinese torture method. 
big breakfast
If you're trying to gain weight and can't, this picture may trigger anxiety. But there's an easier way. [Photo courtesy Pixabay]

Wake Up Earlier

One of the simplest and most effective methods for weight loss is intermittent fasting: restricting calories by increasing the amount of time spent in a fasted state and decreasing the time spent in a fed state. The opposite is true if the goal to gain weight.
Waking up a couple of hours earlier will allow you to effortlessly consume more calories by increasing your “feeding window.” Your current meal pattern allows you to consume only enough food to maintain your weight. Being awake a bit longer will make it easier to eat an extra meal, which may be all you need to move the needle on the scale. 
What if you’re already waking up early? Perhaps you’re like 10 percent of Americans who skip breakfast3 because you’re either not hungry, or you’re too busy. Either way, I’ve got a solution. Have a shake right after you wake up. Not only does it save time, but it adds 250-500+ calories to your day. A breakfast shake could be the difference between being stuck at maintenance and reaching the necessary calorie surplus. It may seem annoying at first, but eventually you’ll adapt and notice you're already hungry as you get out of bed.

Forget “Eating Clean”

The idea of “eating clean” leads us to believe that some foods are inherently “good” and others are inherently “bad.” But no one has ever dropped dead from a Pop Tart, just like no one has gotten up out of bed ripped and healthy from a few servings of peas and carrots. This is not to say that we should opt for the mint chocolate chip ice cream over apples and bananas, but being too restrictive in your diet makes it unnecessarily difficult to eat enough. 
White sugar and flour have no fiber or nutrients and thus do very little in terms of satiety. That's why it’s so easy to eat a thousand calories worth of donuts in one sitting, but almost impossible to do the same with broccoli. If you’re already getting the majority of your calories (80-90 percent) from whole, minimally-processed foods, don’t be afraid to indulge in your favorite not-so-nutrient-dense snacks. 

Change Your Macros

Protein has been shown to decrease appetite due to how slowly it is digested.4,5 If you went out to dinner and ordered the biggest, leanest steak on the menu, chances are you didn't finish the sides, and skipped dessert. And you probably ended up feeling stuffed for the rest of the day.
This isn’t to say that you should avoid protein. It’s still the most important macronutrient when it comes to building lean muscle tissue. But plenty of research suggests you don't need to consume more than 1g of protein per pound of bodyweight.6 Aiming to stay within 0.8-1g per pound while increasing your carbohydrate intake could make it much easier to fit in more calories.

Drink Your Calories

Liquid calories elicit a weak appetitive response when compared to solid foods.7 So although drinking calories can be the worst thing to do if your goal is weight loss, it is an effective method for those looking to gain weight and build muscle.
I don't recommend getting any more than 10-15 percent of your daily intake from liquid calories. Avoid sugary drinks like soda, opting instead for milk (whole, rice, almond, etc.) and fruit juice. And to get more nutrient-dense calories in less time, add one or two homemade meal replacement shakes to your plan. Here's a recipe I've used:
Homemade Weight Gain Shake Recipe
  • 1 scoop whey protein
  • 2 Tablespoons peanut butter
  • 1 banana
  • 1/2 cup oatmeal
  • 1 cup almond milk
Directions: Throw all ingredients into a blender for 30-60 seconds. 

Increase Caloric Density 

Eating an additional 250-500 calories per day is typically enough to go from maintenance calories to a healthy surplus. Getting in that many more calories may be possible by simply increasing the caloric density of your existing meals, without increasing food volume. 
For example: 
  • Use whole milk instead of skim or 2 percent. 
  • Instead of water in your oatmeal, use almond milk. 
  • Substitute that handful of grapes for a handful of almonds.
  • Drink orange juice instead of water.


These may seem like small changes, but they add up. Incorporating enough of them in the day will help get the needle moving. 

Eat First, Drink Last

Drinking water with your meals has been shown to increase satiety,8 making you feel fuller, faster. That's great for someone whose goal is weight loss, it doesn’t help much when the goal is weight gain. Try to avoid drinking too much water right before or during your meals. The sheer volume of the fluid will make it more difficult to eat more food. Instead, have the majority of your fluids throughout the day, in between meals.

Increase Meal Frequency

Consuming 3,000 calories over three sittings is much more challenging than spreading the same amount of calories over six meals. If you’re finding it hard to eat enough calories, I recommend eating smaller, more frequent meals. If I consume five slices of greasy pizza, I find that I typically won’t be hungry for another six hours. On the other hand, if I have some sweet potatoes and chicken, I’m ready for another meal much sooner. 
Another way to increase calorie intake is to munch on something in between meals. Some people might even find it helpful to include a pre-breakfast and/or pre-bedtime snack.

Learn to Cook

If you want to build muscle, you’re going to have to eat more food than you want to, at least at first. That task will be much harder if the food you’re eating six times a day resembles sludge the lunch lady slapped onto your tray in your middle school cafeteria.
This is why you should learn to cook. Consuming enough calories to grow becomes a breeze when you actually enjoy what you’re eating. Knowing your way around the kitchen will also allow you to prep your meals in advance. And because we all live extremely busy lives these days, having food readily available makes it that much less likely that you’ll end up short on calories for the day.

Small Changes, Big Mass Gains

When your energy needs exceed your appetite, eating enough to reach a caloric surplus can seem like mission impossible. But it doesn’t have to be that way. Put these simple practices into action, and you might find you’re not destined to remain a skinny guy after all. 
Trying to gain mass but stay Paleo?
1. Hand, Gregory A., Robin P. Shook, Amanda E. Paluch, Meghan Baruth, E. Patrick Crowley, Jason R. Jaggers, Vivek K. Prasad, Thomas G. Hurley, James R. Hebert, Daniel P. O'connor, Edward Archer, Stephanie Burgess, and Steven N. Blair. "The Energy Balance Study: The Design and Baseline Results for a Longitudinal Study of Energy Balance." Research Quarterly for Exercise and Sport 84, no. 3 (2013): 275-86. doi:10.1080/02701367.2013.816224. 
2. Levine, J. A. "Role of Nonexercise Activity Thermogenesis in Resistance to Fat Gain in Humans." Science 283, no. 5399 (1999): 212-14. doi:10.1126/science.283.5399.212. 
3. "31 Million U.S. Consumers Skip Breakfast Each Day, Reports NPD." NPD Group. 2011. Accessed June 08, 2016.  
4. David S Weigle, Patricia A Breen, Colleen C Matthys, Holly S Callahan, Kaatje E Meeuws, Verna R Burden, and Jonathan Q Purnell. "A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations." American Journal of Clinical Nutrition. July 2005 vol. 82 no. 1 41-48.
5. Bilsborough S, Mann N. "A review of issues of dietary protein intake in humans." International Journal of Sport Nutrition and Exercise Metabolism. 2006 Apr;16(2):129-52.
6.  Phillips, Stuart M., and Luc J.c. Van Loon. "Dietary Protein for Athletes: From Requirements to Optimum Adaptation." Journal of Sports Sciences 29, no. Sup1 (2011). doi:10.1080/02640414.2011.619204. 
7.  Mattes, Richard D., and Wayne W. Campbell. "Effects of Food Form and Timing of Ingestion on Appetite and Energy Intake in Lean Young Adults and in Young Adults with Obesity." Journal of the American Dietetic Association 109, no. 3 (2009): 430-37. doi:10.1016/j.jada.2008.11.031. 
8. Lappalainen R, Mennen L, van Weert L, Mykkänen H. "Drinking water with a meal: a simple method of coping with feelings of hunger, satiety and desire to eat." European Journal of Clinical Nutrition. 1993 Nov;47(11):815-9.