Not Gaining Weight in a Calorie Surplus?

19 October 20265 min read

A banana smoothie in a glass next to a a bowl of nuts. — Photo by Elena Leya on Unsplash.

If you’re eating more but not gaining weight, your surplus is probably smaller than you think. You may burn more than you estimated, eat less at other meals without noticing, or move more when you eat more. Give it two to four weeks and compare weekly averages. If nothing moves, add 100 to 200 calories a day.

In brief

The NHS suggests adults who want to gain weight add around 300 to 500 extra calories a day.
Some bodies gain far more easily than others. In a 1990 study of 12 pairs of young male twins eating the same extra food, gains ranged from 4.3 kg to 13.3 kg.
Some people move more when they eat more. In a 1999 study of 16 adults, two thirds of the extra calories they burned went on everyday movement like fidgeting.
The NHS says to see a GP if you've lost weight without changing your diet or exercise.

Can you be in a calorie surplus and not gain weight?

Not for long. If you eat more than you burn, your weight goes up over a few weeks. But your surplus is an estimate, and estimates can be off by a lot.

Most calorie targets start from a calculator. Your real needs can be higher than it says, especially if you’re active or on your feet all day. If you’ve never checked your target against your own weight trend, start there. We walk through it in how do I find my maintenance calories.

Why am I eating more but not gaining weight?

There are a few usual causes, and you may have more than one. Use the table to spot yours.

Possible cause	Signs	What to try
You burn more than you thought	Your target came from a calculator and has never changed	Find your real maintenance from your own weight trend
You eat less at other times	Big days are followed by small ones, or you skip meals when busy	Look at your weekly total, not your best days
You move more when you eat more	Hard to notice; your weight just stays flat	Add a little more food rather than cutting back on movement
Your activity went up	You started training or cardio around the same time	Count it in your maintenance, or add food to cover it
Logging misses things	You log big meals but not drinks, snacks or oil	Log everything for two weeks, then look at the totals

The third cause, moving more, catches many people out. In a 1999 study, 16 adults ate 1,000 extra calories a day for 8 weeks. Two thirds of the extra calories their bodies burned went on everyday movement, not exercise. Some people stored about ten times more fat than others, and those whose everyday movement rose most stored the least. We explain this in what is NEAT.

Some people also eat less after a big stretch of eating. In a small 1994 study, men ate about 1,000 extra calories a day for three weeks. Afterwards, the younger men ate about 500 calories a day less than their usual intake, without being asked to, and lost the weight they’d gained. The older men didn’t. A big dinner followed by a light next day can be a milder version of this.

Missed snacks, drinks and oil can hide a surplus, just as they hide a deficit. We cover why in why do I underestimate how much I’ve eaten.

Do I just have a fast metabolism?

Bodies do differ, sometimes a lot. But in the research, people who eat enough extra food still gain, just at different speeds.

In a 1990 study, 12 pairs of young male identical twins ate 1,000 extra calories a day, 6 days a week, for 84 days. On average they gained 8.1 kg. Across the group, gains ranged from 4.3 kg to 13.3 kg, and twins tended to respond like each other. The researchers thought genes were likely involved.

So if a friend gains on extra food that barely moves your scale, nothing is wrong with you. You may just need a bigger surplus than they do.

How long before a surplus shows on the scale?

Usually two to four weeks. The scale may jump in the first few days, but much of that is extra food, salt and water. After that, real gains are small, so normal daily ups and downs can hide them.

Compare weekly averages, not single mornings. If your average hasn’t moved after three or four weeks of eating more, your surplus is probably too small. We explain how to read daily ups and downs in when will changes show on the scale.

How much more should you eat to gain weight?

The NHS suggests adults add around 300 to 500 extra calories a day, and gain gradually. We’d add those on top of your maintenance, then adjust based on your weekly average. Our weight gain calorie calculator gives you a gentler starting target, matching the Ori app.

Say your maintenance is about 2,300 calories a day. You’d aim for roughly 2,600 to 2,800. Still flat after three or four weeks? Add a little more, say 100 to 200 calories a day, and check again.

If you lift weights and want mostly muscle, a slower pace may suit you. A 2019 review of advice for newer bodybuilders suggested gaining about 0.25% to 0.5% of body weight a week. For a 70 kg person that’s roughly 0.2 to 0.35 kg a week. It’s aimed at people training hard, so treat it as a guide.

How do you eat more when you’re not hungry?

Make each bite count for more, and eat more often. Many of these tips come from the NHS page on gaining weight.

Eat smaller meals more often, with snacks in between.
Add easy extras to meals, like cheese, nuts or seeds.
Have milkshakes or other high-calorie drinks between meals rather than just before them, so they don’t fill you up.
Keep easy snacks around, like yoghurt or rice pudding.
Try strength training or yoga. The NHS says exercise can also improve your appetite.

Treats are fine, but the NHS suggests not relying on chocolate, cakes and sugary drinks. Aim for a mix of foods, with protein from things like eggs, fish, beans and lean meat.

Where Ori fits

With Premium, Ori looks at your food logs and weight trend each week and can adjust your calorie target. That way you’re not stuck on a number that isn’t working. Look Away Weighing, also part of Premium, reads your bathroom scale through your phone camera without showing you the number. If that sounds useful, you can try Ori here.

Sources

A gentle safety note

Ori supports general wellness. It is not medical care. If you have a history of disordered eating, are pregnant or breastfeeding, take medicines that affect weight or appetite, or have a clinical nutrition need, speak with a qualified healthcare professional before changing your intake or weight goal.

Read Ori's Health Disclaimer