10 High calorie foods to help skinny guys build muscle

Written by Martin Ebner
Last updated August 2026

You already know what's calorific. Everyone does. If eating a lot were the whole job you'd have solved this years ago with a family bag of Doritos and a determined expression.

The reason you're not gaining isn't a knowledge problem. It's an appetite problem. You get four bites into the third meal of the day and something in you quietly gives up.

So this list isn't the fifty most calorie dense things in a supermarket. It's ten foods worth eating when you're trying to build, and at the bottom I've put the part nobody writes about, which is what to do when you can't face another plate of food.

THE QUESTION I’D ASK ABOUT EVERYTHING ON YOUR PLATE

Here's the one I use on my own food, and on my clients':

IS THIS INGREDIENT ADDING NUTRITION VALUE, OR IS IT JUST ADDING CALORIES?

For most people that question is about taking things away. The rice next to a meal that already had plenty. The bread that came with the shake and the coffee.

FOR YOU IT RUNS THE OTHER WAY

You need the calories, so the question becomes: which of these is bringing something else along with them? Protein, fats worth having, fibre, minerals. Because you can hit your number on ice cream and pastry, and you'll get bigger, and you'll feel rotten doing it and you won't like what you see.

That's your main filter. Every food below passes it.

10 BEST HIGH CALORIE FOODS FOR SKINNY GUYS TO BUILD MUSCLE

Now that we're clear that the quantity and quality of calories you consume matter, let's take a look at ten of the best high-calorie foods for skinny guys looking to add serious muscle mass.

1. NUTS AND SEEDS

Enormous calories for very little volume, which is the exact trade you want. A handful of almonds is around 160 calories and takes ten seconds. Walnuts, cashews, pumpkin seeds, all fine.

Keep a bag somewhere you'll see it. Nobody has ever gained weight from nuts they left in a cupboard.

2. NUT BUTTER

The same trick, easier to swallow, and much harder to stop eating. A tablespoon straight from the jar is about 100 calories with no chewing and no plate.

Buy the kind whose ingredient list says nuts, and possibly salt. The ones with palm oil and sugar in them are just a worse version of the same idea.

3. OLIVE OIL

The most underrated ingredient on this list, and the easiest win you'll get every day of the week.

A tablespoon over whatever you've already cooked is roughly 120 calories that you won’t notice eating. Do it twice a day and you've added 240 without touching your appetite. There is no other food on earth that gives you that deal.

4. AVOCADO

Around 240 calories each, plus potassium and fibre. Goes with eggs, goes on toast, goes in a shake without ruining it.

If you find them boring, and plenty of people do, this is one to hide amoungst other ingredients rather than one to force.

5. WEIGHT GAINER POWDERS AND SHAKES

I'm generally a little sceptical of supplements and I say so often. This is the exception, and it's a real one.

If you struggle to eat enough, drinking calories is easier than chewing them. That isn't a shortcut, it's just physics. A shake with oats, milk, banana, peanut butter and a scoop of protein will do 700 calories in about four minutes.

Make your own before you buy a tub of anything. It's cheaper, it's better, and you'll know what's in it.

6. FULL-FAT MILK AND YOGURT

Full fat, not the skimmed version. You're not trying to save calories, you're trying to find them, and the fat is the point.

Greek yoghurt in particular is doing two jobs at once, calories and a proper hit of protein. A big bowl with honey and nuts is one of the easiest 600 calories going.

7. CHEESE

Calorie dense, high in protein, and it makes vegetables taste like something you'd choose. Grate it over everything.

Manchego, cheddar, whatever you like. This is one of the rare places where the enjoyable option and the useful option are the same option.

8. BUTTER

Real butter, on and in things. About 100 calories a tablespoon and it disappears into food without adding bulk to your stomach.

Cook in it, finish vegetables with it, put it on the potatoes. Same logic as the olive oil, different flavour.

9. FATTY FISH

Salmon, mackerel, sardines. Calories, complete protein, and omega 3s that most people are short of.

Tinned sardines are about two euros and take no cooking at all. Not glamorous. Extremely effective.

10. CARBS, CARBS AND MORE CARBS

Rice, oats, pasta, potatoes, bread. This is where the bulk of your calories will come from.

Weigh your grains dry, by the way. Cooked weights include water and they'll flatter you into eating less than you think you are.

NOW THE BIT THAT MATTERS

Everything above is easy. Here's the hard part, and it's the reason most skinny guys stay skinny.

YOU HAVE TO EAT WHEN YOU’RE NOT HUNGRY

That's it. That's the whole discipline. Not willpower in the gym, willpower at the kitchen counter at four in the afternoon when you'd rather not.

A few things that make it survivable.

EAT MORE OFTEN RATHER THAN MORE PER SITTING

Five or six smaller meals beats three you can't finish. Your stomach adjusts to this over a few weeks, which is worth knowing when the first fortnight feels grim.

DRINK SOME OF IT

See number five. When your appetite has gone, liquid still goes down.

DON’T FILL UP ON AIR

Salad, soup, fizzy drinks and litres of water before a meal will beat you. Save the water for between meals.

WRITE DOWN WHAT YOU ACTUALLY EAT FOR 5 DAYS

Not to judge it. Just to see it. Almost everyone who tells me they're eating loads is eating about two thirds of what they think, and you can't fix a number you've never looked at.

A WORD ABOUT TIME

You'll be told you can transform in twelve weeks. You can change quite a lot in twelve weeks. You will not undo a decade of a fast metabolism and a small appetite in twelve weeks, and anyone promising that is selling something.

Muscle goes on slowly for everyone, and likely even slower for you. That isn't a reason to stop. It's a reason to stop measuring yourself against a schedule someone made up.

Eat a bit more than yesterday. Do that for long enough and the arithmetic wins.

A BIT WORTH KEEPING

You don't need a secret food. You need a slightly bigger appetite and a lot more patience than the internet suggests.

Pick three things off this list you'd enjoy eating, add them to what you already eat, and leave everything else alone for a month.

If you want the food and training put together, read my hardgainer workout and diet guide.

If you want to know why your body puts weight on the way it does, I've written about male body types separately.

If you want more of this, I write a wee newsletter called Check It Oot. Once or twice a month, and never anything you'd need to unsubscribe from in a hurry.

Cheers, Martin