I've been on a diet for a week and not losing weight: is it normal?
Escrito por
Dr. Laura MéndezMedical specialist in Endocrinology and Nutrition
GMC No. 7284191 · General Medical Council (UK)
It's completely normal not to lose weight in the first week of dieting. The body retains fluids when changing diet, stool and glycogen weigh, and fat is lost more slowly than the scale shows. A week is very little time: real progress is measured in weeks, not days.
Why the scale doesn't move in the first week
When you start eating differently, your body takes time to adapt. In the first few days several things can happen at once: you retain fluids, your glycogen stores shift (which pull water with them) and your digestion readjusts. All of that has weight and can hide the fat you are actually losing.
On top of that, if you've started exercising, your muscles retain water to repair themselves. It's possible to lose fat while the scale doesn't drop, or even rises slightly, for a few days.
How much weight is realistic to lose
Losing faster usually means losing water and muscle, not fat, and encourages the rebound effect. A slow, steady pace is what really lasts over time.
How to measure real progress
- Always weigh yourself under the same conditions (fasted, once a week).
- Use a tape measure: waist, hips and arm say more than the scale.
- Take photos every 2–3 weeks with the same lighting and clothing.
- Notice how your clothes fit and your energy and sleep.
The scale is only one data point. If you obsess over the daily number, you'll get frustrated just when you're making the most progress.
When should you worry?
A week without changes is no cause for alarm. But if 4–6 weeks pass while following the plan well and you notice absolutely nothing (no weight, no measurements, no clothing change), it makes sense to review the situation with a doctor to rule out causes such as hypothyroidism or to adjust the approach.
At DoctorLife we assess your case at no cost and tell you honestly whether what you're doing makes sense or whether it's worth changing strategy.
Frequently asked questions
Is it normal not to lose weight in the first week of a diet?
Yes, it's very normal. In the first week fluid retention, glycogen and digestion all play a role and can hide the fat you're losing. Real progress shows over several weeks.
Why have I gained weight after starting to exercise?
When you start exercising, muscles retain water to repair themselves, which can raise your weight for a few days. It isn't fat. Over time, exercise helps you lose fat and improve body composition.
How often should I weigh myself?
Ideally once a week, under the same conditions (fasted, without clothing). Weighing yourself daily creates anxiety because of the normal variations from water and food.
How much weight is healthy to lose per week?
Between 0.5 and 1 kg per week for most people. Losing faster usually involves losing muscle and water, and increases the risk of regaining the weight.
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Esta guía forma parte de Losing weight with medical supervision.
