Why is it so hard for me to gain weight

If the scale has not moved in months, the first conclusion is usually “I have a fast metabolism.” In practice that is almost never the main reason — energy expenditure does vary between people, but far less than most assume. Much more often, weekly calorie intake simply is not higher than expenditure, and training is not giving the body a reason to build muscle.

First: measure what you actually eat

Before changing anything, weigh and log everything you eat for seven days straight, weekend included. Do not eyeball it — the difference between 40 g and 80 g of peanut butter is about 250 kcal, and that is the entire difference between growing and standing still.

The typical pattern in naturally lean people: two big meals, a stuffed feeling, and 2,000 kcal for the whole day. On top of that, leaner people tend to move more without noticing — fidgeting, extra walking, general restlessness — so part of any surplus is burned off before it registers.

How many calories you need

A rough starting estimate for someone training 3-4 times a week: 30-35 kcal per kilogram of body weight. At 70 kg that is 2,100-2,450 kcal per day for maintenance.

Add 300-500 kcal per day on top. The target is a gain of 0.25-0.5% of body weight per week — at 70 kg that is 175-350 grams weekly, or roughly 1-1.5 kg per month. Faster than that usually means more fat and water than muscle.

Weigh yourself 4-5 mornings a week, always after the bathroom and before breakfast, then compare this week's average to last week's. A single day tells you nothing. If the average is flat two weeks in a row, add another 200 kcal per day.

How to eat more when you have no appetite

For most people the problem is not willpower, it is food volume. The fix is choosing more calorie-dense food and eating more often.

• 4-5 meals a day instead of two big ones, spaced 3-4 hours apart.
• Liquid calories. A shake with 400 ml milk, 80 g oats, one banana and 30 g peanut butter is about 700 kcal and goes down in two minutes.
• Add fats. One tablespoon of oil is around 120 kcal, 30 g of walnuts around 200 kcal — calories that take up almost no space in your stomach.
• Pick the less bulky version. Dried fruit instead of fresh, meat and rice instead of a giant salad, full-fat yogurt instead of non-fat.
• Do not drink half a litre of water or soda in the 30 minutes before a meal.
• If large amounts of vegetables and legumes bloat you, cut them back temporarily; 25-30 g of fibre a day is plenty.

Macronutrient split

• Protein: 1.6-2.2 g per kg — at 70 kg that is 112-154 g a day, easiest as 4 meals of 30-40 g.
• Fat: 0.8-1.2 g per kg — 56-84 g at 70 kg.
• Carbohydrates: everything left over, usually 4-7 g per kg. They fuel heavy sets and are the simplest way to add calories.

Supplements are not the deciding factor here — food does the same job. If protein powder is easier for you than cooking a fourth meal, that is convenience, not necessity.

Training: making the surplus become muscle

Without a training stimulus, a calorie surplus ends up as body fat. The sensible minimum:

1. 3-4 strength sessions per week, either full body or an upper/lower split.
2. 10-20 working sets per muscle group per week, mostly in the 5-12 rep range.
3. Take sets to within 1-3 reps of failure. The last two reps should be slow and hard.
4. Stick to the basic patterns: squat, deadlift or Romanian deadlift, bench press, row, pull-up or pulldown, overhead press.
5. Log your weights and reps. Progression: once you hit the top of the rep range in every set, add 2.5 kg on leg exercises and 1.25-2.5 kg on upper body exercises.

Rest 2-3 minutes between heavy sets. Keep cardio to 2 sessions of 20-30 minutes a week — it is not forbidden, but every hour of running has to be paid back with food.

If the weight on the bar has not moved in three months, the problem is the program or the recovery, not your genetics.

Sleep, stress and consistency

Sleep 7-9 hours. On less, training quality drops and daytime fatigue kills your appetite. Skipping meals during a busy stretch is the most common reason the weekly average comes out lower than you think: five perfect days plus two days that are 1,200 kcal short wipe out the entire surplus.

When to see a doctor

Most cases come down to intake, but see a doctor if:

• you are losing weight unintentionally, especially more than 5% of body weight over 6-12 months;
• along with being underweight you have a fast pulse, hand tremor, sweating and poor heat tolerance (possible overactive thyroid);
• you have chronic diarrhoea, bloating, fatty stools or pain after eating (coeliac disease and other absorption problems);
• you have constant thirst, frequent urination and marked fatigue;
• you have eaten to plan for 8-12 weeks with no change on the scale at all;
• you notice yourself avoiding food, counting every bite, or feeling guilty after eating.

The basic workup is simple: complete blood count, TSH, glucose, ferritin and coeliac markers.

The short version

• Weigh your food for seven days — without that number you are guessing.
• Maintenance is roughly 30-35 kcal/kg; add 300-500 kcal and aim for 0.25-0.5% of body weight per week.
• Protein 1.6-2.2 g/kg, the rest from carbs and fat; liquid calories solve the appetite problem.
• 3-4 strength sessions a week, 10-20 sets per muscle group, and log your progression.
• If nothing changes over 8-12 weeks of consistent intake, get the basic bloodwork done.