How to stop regaining weight

You lost the weight. Some time after, the number started coming back up: a kilo, then another. Now you're watching it with a feeling you recognise, and the question is no longer how to maintain. It's how to make this stop.

First, the reassurance, because it's true: this is the most common thing that happens after a diet, and it is far easier to stop early than it was to lose in the first place. You don't need another diet. You need to know how much of the gain is real, a line, and one small correction.

Why the weight comes back

It isn't a lack of willpower. Three things push in the same direction after weight loss, and nobody warns you about any of them.

Your appetite goes up. A smaller body needs less food, but it doesn't ask for less. A study of people losing weight without knowing it, run partly by researchers at the US National Institutes of Health, estimated that appetite rises by roughly 100 calories a day for every kilogram lost, which is about three times the drop in what your body actually burns. Lose 10 kg and you can be hungrier than you were before you started, while needing less food.

Your maintenance is lower than you remember. A lighter body burns less, and you move a little less without noticing. The amount you ate before the diet now produces a surplus.

The structure goes. During the diet you were logging, weighing and planning. At the goal, most of that stops, and most apps stop with it. The feedback that kept you on course disappears just when you need it most.

Put those together and regain is the default. In a review of US weight-loss studies, five years after a structured programme people had kept off only about a fifth to a third of what they lost. That isn't a reason to give up. It's a reason to have a plan, because the people who keep it off are the ones who have one.

Step 1: find out how much of it is real

Not every kilo on the scale is fat. Before you change anything, separate the two.

• If you came off a diet in the last few weeks, expect the scale to rise by around a kilo as you eat more. That is water and stored carbohydrate returning to your muscles. It is not fat, and it happens to everyone who stops dieting.
• Daily weight swings by one to two kilos with salt, carbohydrate, sleep, alcohol and your menstrual cycle. A single high morning means nothing. Why the scale lies explains the swing in detail.

So weigh most mornings for two weeks and compare the weekly averages. If this week's average is above the one two weeks earlier, and the one before that, the trend is real. If it's bouncing around one level, you may already be holding.

Step 2: draw a line

Decide on a weight range you're going to hold. It should be a couple of percent of your body weight wide, wide enough to contain your normal daily swing. Anywhere inside it, you do nothing.

This is the single most useful thing in the whole article, because regain rarely arrives in one go. It arrives a kilo at a time, and each kilo feels too small to act on. A line turns "I've put on a bit" into a clear trigger: when your weekly average sits above the top of the range for two weeks running, you act. Not before, and not later.

You also get to choose where the line goes. If you've regained a few kilos and feel well at this weight, it's a legitimate choice to draw the range here and hold, rather than going back down. Stopping the climb is the win. Getting back to your lowest weight is a separate decision, and it can wait.

Step 3: a small correction, not a new diet

When the trend is real, the answer is a small, boring adjustment, not another diet. Take 100 to 200 calories a day off what you're eating now, or add a daily walk, or both, and hold that for two to three weeks. Then look at the trend again.

That's enough. A drift of a kilo a month is a surplus of only about 250 calories a day, so a small change closes most of it. The temptation is to start a strict diet instead, and that is usually what restarts the cycle: a hard cut, a rebound, and another round of regain.

If you don't know what you're eating now, start there. Use the calculator below to estimate your maintenance at your current weight. It will probably be lower than the figure you had in mind before your diet.

Treat that as a starting point, not the answer. Your real maintenance is whatever amount holds your weekly average steady, and how many calories to maintain your weight shows how to measure it from your own data. The maintenance calorie calculator is also on a page of its own.

Step 4: log again, for a few weeks

The fastest way to find where a 250-calorie surplus is coming from is to write down what you eat for two or three weeks. It is usually somewhere you would not guess: a larger portion at dinner that crept in over time, weekend meals out, drinks.

You don't have to log perfectly to learn something. The more detail you give, such as portions and how food was cooked, the more accurate the picture, but a rough log of every meal teaches you more than a careful log of half of them. Once you've found the gap and the trend has turned, you can loosen off again.

Step 5: keep the habits that protect you

The people in the US National Weight Control Registry, who have kept off at least 13.6 kg (30 lb) for a year or more, share a small set of habits. They weigh themselves regularly. They stay active. They eat in a fairly consistent way through the week and at weekends.

Two more matter specifically for regain:

• Keep your protein up. It's the most filling of the three macros, which helps with the extra appetite, and it protects the muscle you kept while losing.
• Keep training. Muscle is what keeps your maintenance number from falling further, and training makes extra food go somewhere useful.

How to maintain weight after losing it covers these habits for the first months after a diet, if you are early enough to set them up before the drift starts.

What not to do

• Don't wait for it to become a big number. Two kilos takes a few weeks to reverse. Eight kilos takes months.
• Don't panic at one weigh-in. React to the weekly trend, not to a morning.
• Don't treat it as a failure. Regain is what bodies do by default after weight loss. Catching it is the skill, and it is one you can learn.

Let Sophia watch the trend

The difficult thing about regain is that it's slow. Two weeks of drift look almost the same as two weeks of normal swing, so people either react to noise or notice the trend only when it's large. And most apps go quiet once you reach your goal, at the point where the hardest part begins.

Sophia doesn't. She holds your range, reads your weekly trend rather than any single morning, and tells you plainly when nothing is happening, which is the result you want. When a drift is real, she tells you early, while it's still a small correction, and suggests the change that settles it.