Mistake #1: Not changing your calorie plan as you lose weight. The fallacy of
"1200 calorie diet" plans and like.
Most people fix their calorie intake to a given number and expect to lose weight at same constant rate over a period of weeks. Hence, dieters look for 1000 calorie or 1800 calorie diet plans on internet. The fixed calorie diet plans don't work. If you burn 3000 calories a day at 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 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 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 calorie reduction and exercise a lot. For people who have to lose more than 20 pounds (10kgs), 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 weight 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 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, bigger calorie expenditure drop. The leaner dieter, greater 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 rate of metabolic drop. Here is general rule: bigger you are, smaller rate of metabolic drop. The more weight you lose, 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.
Mistake #2: Overreporting "extra" calorie expenditure of exercise
Most people count calories they spend exercising as "extra" calories. There is a difference between calories burned while exercising and "extra" calories burned exercising. Here is an example: you burn 300 calories on treadmill instead of your usual activity (watching TV at home); in reality, you have to subtract calories you would have spent watching TV from these 300 calories to calculate how many additional calories you burned. Let's say that watching TV, you would have burned 80 calories. In this specific case, you have expended 300 calories while exercising, and 220 "extra" calories.
Calorie counters mindlessly add calories burned exercising as "extra" and in some cases, this practice can significantly influence calorie calculations. Hence, calorie software counts part of your usual activities that overlaps with extra activities twice.
How to estimate "extra" calories burned exercising?
In order to make calculations more accurate, I shall first introduce concept of MET values. MET values are a convenient way to calculate calorie cost of activities. MET values are multiples of resting energy expenditure per time. In plain English, a MET = 3 means burning 3 times more calories than resting. A MET = 1 signifies how many calories you burn at rest (your Resting Metabolic Rate or Basal Metabolic Rate). Whatever you do, you burn calories at a rate of at least MET = 1 with only exception being sleeping which has MET = 0.9. During day, most activities include sitting and walking which have MET values between 1.2 and 3. Your total daily energy expenditure is calculated by multiplying your Resting Metabolic Rate by average MET of all your activities. Is your head spinning?
Let's use a real world example. Consider a female person with a Resting Metabolic Rate of 1200 calories a day. One day has 1440 minutes. Our example lady is burning 1200/1440 = 0.84 calories per minute at rest, which signifies a MET = 1. Let's say our example woman just returned from an aerobics class, where she exercised for 30 minutes. General aerobic class training has a MET = 6. Our example lady has just burned 30 (minutes) x 6 (MET) * 0.84 (calories per minute) = 151 calories while exercising. Suppose our lady would have chatted on internet instead of exercising (MET = 1.5). In this example, woman substituted chatting on internet with aerobic exercising. Remember, that every time you do something you substitute one activity for another. In order to get extra calories, we have to subtract 1.5 (chatting) from 6 (exercising). Now let's calculate extra calories: 30 (minutes) * (6 - 1.5) (MET value) * 0.84 = 113 calories.
Let's consider what a standard calorie counter would have done. First, it will assume an average calorie burn rate of 1 calorie per minute. Then counter will find that exercising for 30 minutes will yield 30 (minutes) * 6 (MET) * 1 (calories per minute) = 180 calories. The calorie counter will add these 180 calories to your daily expenditure without considering that a part of these 180 calories is already accounted by your usual activities.
Do you now see difference between 113 calories and 180 calories? If that woman spends 5 hours a week in that aerobics class, standard calorie counters will overreport her calorie output by: (180-113) * 10 = 670 calories a week. The woman will be fooled that her metabolic rate has dropped while she just overestimated her calorie expenditure. Enter weight loss plateau, wasted time and efforts. Do you have time for trial and error calorie estimations?
