How Long It Takes to Reach Your Goal Weight

Most goal weights fail on the timetable rather than the target. What breaks is the assumption that it arrives by a wedding in nine weeks, and when it obviously will not, the plan gets abandoned rather than extended.

The arithmetic that sets your date

A pound of body fat stores in the region of 3,500 calories, and a kilogram roughly 7,700. Run 500 calories a day under maintenance and you are 3,500 down by the end of the week, which is about a pound.

So a 20 lb target at 500 a day is 20 weeks. Just under five months. Want it in ten weeks and you need a 1,000 calorie daily deficit with no loose days, which for most people means eating 1,200 to 1,500 calories. That is where adherence collapses.

Metric is the same: ten kilos is 77,000 calories, so at 500 a day that is 154 days, about 22 weeks.

Why the first two weeks lie

Most people drop 3 to 5 lb in the first fortnight of any diet, and little of it is fat. Cutting carbohydrate depletes glycogen, and each gram of glycogen holds around 3 g of water with it.

The water came off once and cannot come off twice. Extrapolate from that first fortnight and you build a timeline roughly twice as fast as reality, then conclude you have failed in week four. Start counting from week three.

Picking a rate you can hold

The common guidance is 0.5 to 2 lb a week, but the useful version scales with your size. About 1 per cent of body weight a week is the ceiling before muscle loss and hunger start winning.

Why the same deficit gets harder

A 200 lb person can take 2 lb a week, which needs a 1,000 calorie daily deficit off a maintenance level that might be 2,600. That leaves 1,600 calories, which is tight but liveable. A 140 lb person at the same 1 per cent is 1.4 lb a week, needing 700 a day off a maintenance closer to 1,900. That leaves 1,200, a different experience entirely.

Maintenance itself falls as you get lighter. Dropping 20 lb from 200 cuts daily maintenance by roughly 100 to 150 calories, so meals that produced a 500 calorie deficit in January produce closer to 370 by April. Recalculate every 10 to 15 lb. Our piece on using TDEE for weight loss covers resetting the number as you go.

Using the weight calculator

Start with current weight and goal weight, and take the current figure properly: morning, before eating, same scale. Weight swings 2 to 4 lb across a day, so an evening reading compared against a morning one invents progress that does not exist.

For the goal, the calculator gives a healthy range for your height rather than one number, and the range is wide on purpose. Pick something near the middle that you have actually held before as an adult, because a weight you sustained at 25 is far more achievable than one you have never seen.

Then enter your intended weekly rate. This is the field to be honest in. The output is a date, and the date is the point: it tells you whether this is a two month job or a nine month one before you commit.

Weigh daily but read the weekly average. A single Tuesday reading is mostly salt, sleep and digestion. Our note on calorie deficits covers holding the deficit without counting every gram.

Common questions

How long to lose 20 lb? At 1 lb a week, twenty weeks. At 1.5 lb a week, about thirteen. Anything promising six weeks is either water, or a deficit that will not survive a normal working month.

Is 3,500 calories per pound accurate? It is an approximation, and it overstates loss slightly over long periods because maintenance drifts down as you shrink. For a few months it is close enough. For a two year projection it is optimistic.

Why did I stall for three weeks? Usually portion creep, a lower maintenance level than before, or water retention hiding real fat loss underneath. Check the trend across four weeks before changing anything, and check your food logging first.

Should I set a goal weight or a goal waist? Both, and the waist is often the better target. If you lift while losing fat, the scale can sit still for a month while your clothes keep getting looser.