Not changing your calorie plan as you lose weight. The fallacy of the “1200 calorie diet” plans and the like.

Most people fix their calorie intake to a given number and expect to lose weight at the same constant rate over a period of weeks. Hence, dieters look for 1000 calorie or 1800 calorie diet plans on the internet. The fixed calorie diet plans don’t work. If you burn 3000 calories a day at the start of a diet, after a week or two of losing some weight, you are no longer burning 3000 calories. Now you might be burning 2800 calories. If you fix your calorie intake in the face of a decreasing calorie expenditure, your weight loss will slow down more and more as you lose weight.

If you want to lose weight at a constant rate, you must repeatedly:

* decrease your calorie intake to accommodate the calorie expenditure drop
* increase your calorie output by exercising more
* do both

I would like to note that you must set realistic slow weight loss goals. If you go for fast weight loss you would not be able to sustain it for a long period unless you go extreme in the calorie reduction and exercise a lot. For people who have to lose more than 20 pounds (10kgs), the goal should be a loss of no more than 2 pounds or 1 kg per week. People who need to lose just a bit of weight should go for weight loss of 1 pound or half a kilogram per week.

Why does my calorie expenditure drop as I lose weight? The most important factors are:

* You weigh less. A smaller body burns less calories both at rest and while active
* You may involuntarily burn fewer calories. Dieters often lack energy and move less
* Calorie restriction suppresses the metabolic rate
* You have less body fat, which may further suppress your metabolic rate

These major factors contribute to an ever-decreasing energy expenditure as one loses weight. The more a dieter cuts calories, the bigger the calorie expenditure drop. The leaner the dieter, the greater the calorie expenditure drop.

Now you must understand that if you want to succeed in losing weight, you have to make changes in your nutrition plan. I recommend burning more calories, because being more active facilitates smaller calorie restriction and milder calorie expenditure drop.

It is very difficult to estimate the rate of the metabolic drop. Here is the general rule: the bigger you are, the smaller the rate of the metabolic drop. The more weight you lose, the more you have to cut calories or increase exercise. If you are overweight you might need to cut just 10 more calories for every lost pound, while if you are lean you might have to cut 60 calories for every pound lost. I picked these numbers just as an example.