Keeping tabs on your changing body is part art and part science. Gaining muscle, retaining water and weighing yourself at different times each day are just a few examples of how your weight can fluctuate a great deal from day to day. Several methods can reveal if you are losing weight, such as taking body measurements, calculating your body mass index and judging how clothes fit. If you use more than one method to track your progress, you will be able to tell more accurately if you have lost weight.
Weigh yourself with a consistent schedule to determine accuracy. Do it in the morning before breakfast, but after going to the bathroom. Remove your clothes and shoes before you weigh yourself. Keep a chart to determine if you've lost weight, or if other factors are contributing to temporary weight gain, like your menstrual cycle.
Calculate your body mass index. Your BMI decreases as you lose weight. Calculate this figure by multiplying your weight in pounds by 703. Divide this figure by your height squared. BMI might increase as you gain muscle mass, and isn't always the most accurate way to determine weight loss.
Measure yourself. Your weight can fluctuate based on how much muscle you gain or lose, and how much water weight you gain or lose. But measurements help you see that your body is getting smaller even when your scale numbers aren't. Measure your abdomen, upper arms, neck, thighs, bust line, chest and butt each week, and compare them with your previous week's measurements.
Monitor the way your clothes fit. Look for looseness in the legs, waist and chest. As you lose weight, your clothes will become looser, and the size you wear will decrease. Check to see if your shoes feel looser, as well, because weight loss can reduce your shoe size.
Measure your body fat. As you lose body fat, you lose weight. Purchase a scale with a body fat measurement device, or have a doctor or fitness professional use calipers to assess your body fat percentage. Use the American Council on Exercise's body fat calculator if you don't have access to other methods. Record your measurement, and compare it with future measurements to determine weight loss.