Written by: Wallace Merriman

Why Do Some People Lose So Much More Weight in the First Week of a Diet?
Posted on:May 18, 2016

If you’re trying to reach a goal weight and you start a new diet plan, odds are good that you’ll lose weight faster at the beginning than you will near the end. There are a variety of factors involved in why, ranging from your starting weight and fitness level to how closely you adhere to your diet. A sustainable diet is always better than a diet that will rapidly take weight off, so talk with your doctor before making any major changes.

Calorie Math and Myths

It may seem logical that if you cut a certain number of calories from your diet every day, you’ll lose weight at a constant rate. However, that isn’t the case. Heavier people typically burn more calories than lighter people because they have higher basal metabolic rates, which is the number of calories your body burns every day for basic processes. Thus, after the first week of your diet has passed and you’ve lost a few pounds, your basal metabolic rate will likely be lower and will continue to decline as you continue to lose weight.

Water Weight

You may have heard that some diets result in a rapid loss of water weight. It’s true, and it can be part of the reason why the weight comes off so quickly after you switch to a new diet. When you cut calories, particularly calories from carbohydrates, your body begins to use up its supplies of glycogen, a carb that is stored with water. Losing that glycogen and the accompanying fluid can result in notable weight loss, since just 2 cups of water weighs 1 pound. After that initial “water weight” comes off, you’ll likely begin to lose at a slower rate.

It’s All Attitude

The way you feel about your weight-loss plan can influence how closely you follow it, and it makes sense that you’d be the most motivated to stick to your diet right after you start it. If you have an ambitious plan to cut 1,000 calories every day, give up sugar and eat more vegetables, for instance, you might abide by it without budging for the first week. That can make a big difference in the initial results you see on the scale, but as time goes on, those results will be less dramatic if you don’t stick as strictly to the diet.

Keeping the Weight Off

Although fad diets may take off a lot of weight right away, the National Institutes of Health cautions against using them because they are not sustainable. To prevent regaining the weight you lose, it’s important to follow an eating plan that is sustainable over the long term. When you are ready to lose weight, talk with your doctor to develop a healthy plan. Losing about 2 pounds a week is a healthy rate of weight loss, but dropping weight faster than that can put you at risk for severe health issues that include gallbladder damage, kidney failure, osteoporosis and heart irregularities.