Hardgainer? How to Build Muscle When You Struggle to Gain Weight
If you are naturally slim and find it hard to put on weight, the answer is almost always the same two things done consistently: eat a little more than your body needs every day, and lift progressively heavier weights three times a week. Most self-described hardgainers are not cursed with a special metabolism. They eat less than they think, more erratically than they realise, and train in a way that does not give muscle a reason to grow. Fix the eating with structure rather than willpower, train the big lifts, and a sensible target is a steady gain of a few hundred grams a week.
Why some people really do find it harder
It is fair to say some people find gaining weight harder than others. Appetite varies. Some people fidget more, walk more and generally burn more energy through daily movement without noticing. Some feel full quickly and forget to eat when busy. Tall, long-limbed men also need more food to fill out a larger frame.
None of that changes the basic rule. If you take in more energy than you use, your body has to put it somewhere, and with the right training, a good share goes to muscle. What it changes is the method. A hardgainer cannot rely on appetite. He needs a system.
A quick note before anything else: if you are underweight and also losing weight without trying, feel unusually tired, or have digestive symptoms, see your GP before starting. The NHS advice for underweight adults covers the medical side and when to get checked.
Step 1: find out what you really eat
Most men who say “I eat loads” are remembering their biggest meals. Track everything for four normal days, including one weekend day, and weigh yourself on the same mornings. Two patterns come up again and again:
- A large dinner and not much else. Coffee for breakfast, a sandwich at the desk at three, then a big evening meal. The total is often well short of what an active man of six foot needs.
- Good days and forgotten days. Weekends are generous, weekdays are thin. The average ends up at maintenance.
Once you know your current average and your weight is stable on it, that average is roughly your maintenance intake. Everything else builds from there.
Step 2: set a modest surplus
Add around 300 to 500 calories a day to your maintenance figure. For most slim men, that produces a gain of roughly a quarter to half a kilo a week. Faster than that and a larger share of the gain tends to be fat; slower and progress becomes hard to see.
Weigh yourself most mornings and track the weekly average. If it has not moved after two weeks, add another 200 calories. Hardgainers often need to make this adjustment two or three times because their bodies respond by moving a little more.
How to actually eat more
This is where most people struggle, so the methods matter more than the numbers:
- Eat four times a day, at fixed times. Breakfast, lunch, a planned afternoon meal and dinner. Put them in your calendar if you need to. Appetite is unreliable; a schedule is not.
- Add calories that do not fill you up. Olive oil on vegetables, nut butter on toast, whole milk instead of skimmed, a handful of nuts and dried fruit. These add energy without much volume.
- Drink some of it. A smoothie made with milk, oats, a banana, peanut butter and yoghurt can easily carry a meal’s worth of energy, and liquids are less filling than solid food.
- Get protein in every meal. Aim for a palm-sized portion or two of meat, fish, eggs, dairy, tofu or pulses each time. Our guide to protein for muscle building covers the amounts.
- Keep starchy carbohydrates generous. Rice, pasta, potatoes, bread and oats fuel training and are easy to scale up.
The NHS also suggests the sensible version of this: more frequent meals and nutritious, energy-dense snacks rather than relying on sugary or fried foods to do the work.
Step 3: train so the food becomes muscle
A surplus without training mostly becomes fat. A surplus with the right training becomes a mixture, with a much larger share of muscle. The right training for a hardgainer is simple and quite heavy:
| Element | What it looks like |
|---|---|
| Frequency | Three full-body sessions a week, 45 to 60 minutes |
| Main lifts | Squat, deadlift or Romanian deadlift, bench or dumbbell press, row, pulldown or chin-up, overhead press |
| Sets and reps | 3 to 4 sets of 6 to 12 reps, stopping one or two reps short of failure |
| Progression | Add a rep or a small amount of weight whenever you hit the top of the range |
| Conditioning | Keep it short: a couple of brief interval sessions a week, plus everyday walking |
Two points matter more than the exercise list. First, progression: if the weights are not slowly going up, the signal to grow is not getting stronger. Second, restraint with cardio. Some is good for your heart and recovery, but long runs on top of a high step count make an already difficult surplus harder still.
Mistakes I see most often
- The “dirty bulk”. Gaining a kilo a week on takeaways mostly produces fat and an unpleasant cut later. Steady is better.
- Program-hopping. Changing routines every three weeks means you never get to the stage where weights climb and muscle follows.
- Too much isolation work. Curls and lateral raises have their place, but the big compound lifts drive most of the change for a beginner.
- Short sleep. Recovery and appetite both suffer when sleep is short. Seven to nine hours is the usual adult recommendation.
- Judging by the mirror after two weeks. Early changes are small. Look at the weekly average weight and your training log instead.
What progress realistically looks like
Expect it to be slow and to come in steps, which is exactly what we plan for with training clients who want to put on size. Weight will rise a little, stall for a week, then rise again. Strength on the main lifts tends to climb quickly in the first few months, which is a good sign the muscle will follow. Clothes usually tell you before the scale does: shirts tighter across the shoulders and upper arms, trousers tighter around the thighs.
An InBody scan can help here. Taken every couple of months under the same conditions, it shows whether the weight you are adding is mostly muscle or mostly fat, so you can adjust the surplus before it drifts. If you are already slim but soft around the middle, our post on being skinny fat covers that slightly different situation.
Where coaching helps
Hardgainers are often the people who benefit most from a coach, because the problems are consistency and progression rather than knowledge. In private 1-1 training in Highgate, we set the eating structure together, track weight and lifts weekly, and adjust the plan before a stall becomes a month. The studio on Archway Road has everything the programme above needs: a squat rack, barbell and plates, dumbbells, a cable station, lat pulldown and seated row.
Questions we get asked
How fast should a skinny guy gain weight?
About a quarter to half a kilo a week is a sensible target for most. Beginners can sit at the upper end; experienced lifters at the lower end.
Do I need mass gainer shakes?
No. A homemade smoothie with milk, oats, banana and nut butter does the same job with better ingredients. Shakes are a convenience, not a necessity.
Will I get fat if I eat more?
Some fat gain is normal during a muscle-building phase. A modest surplus and consistent training keep it to a small share of the total.
How long until I see a difference?
Most people notice changes in strength within a few weeks and visible changes over two to three months of consistent eating and training.
Book with The Highgate House
Ready to start training properly? Email us at [email protected] with the service and the day that suits you, and we will come back to you with times.
Visit The Highgate House · Private personal training
The Highgate House, Archway Road, Highgate, London N6.
