Physiology
Why weight loss slows even when your diet stays the same
Weight loss rarely continues at the same rate because the calorie deficit that started it does not stay constant. As body mass falls, moving and maintaining a smaller body requires less energy. The same food intake can therefore produce a smaller deficit after several months than it did at the beginning.
Dieting can also reduce energy expenditure beyond what body-size changes predict. Resting metabolism may decline modestly, while spontaneous activity such as walking, standing and fidgeting often drops without you noticing. Hunger commonly rises too. This adaptive response is real, but it is not a permanently “damaged” metabolism; it is the body conserving energy when intake remains low.
When progress stalls for several weeks, reassess your current intake, step count and training rather than immediately making a severe cut. A small calorie adjustment or a deliberate increase in daily movement is usually enough. Judge the trend over multiple weeks, preserve protein and strength training, and expect the rate of loss to slow as you get lighter.