Mistake #1: 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 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 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.

Mistake #2: Overreporting the "extra" calorie expenditure of exercise

Most people count the 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 the treadmill instead of your usual activity (watching TV at home); in reality, you have to subtract the 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 the calories burned exercising as "extra" and in some cases, this practice can significantly influence the calorie calculations. Hence, calorie software counts the part of your usual activities that overlaps with the extra activities twice.

How to estimate the "extra" calories burned exercising?

In order to make the calculations more accurate, I shall first introduce the concept of MET values. MET values are a convenient way to calculate the calorie cost of activities. MET values are multiples of the 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 the only exception being sleeping which has MET = 0.9. During the 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 the 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 the internet instead of exercising (MET = 1.5). In this example, the woman substituted chatting on the internet with aerobic exercising. Remember, that every time you do something you substitute one activity for another. In order to get the extra calories, we have to subtract 1.5 (chatting) from 6 (exercising). Now let's calculate the 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 the 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 the difference between 113 calories and 180 calories? If that woman spends 5 hours a week in that aerobics class, the 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 the time for trial and error calorie estimations?

Remember these two rules:

Report only extra activities to your calorie counter. If your walk to your office every day, do not log "walking to office for 30 minutes" as an extra activity. Consider only unusual activities that contribute to extra expended calories! Always subtract the calories you would have burned instead of exercising. A general rule is to subtract from 1.2 to 1.5 from the MET values. In some cases, you need to subtract a greater MET. If you substitute 30 minutes of bodybuilding (MET = 6) for 30 minutes of slow jump rope (MET = 8) then the additional MET would be 8 - 6 = 2.

How to find the MET values of activities based on standard tables?

In order to make the above calculations, you need to know the MET values of activities. Standard tables give: name of activity, duration and calories. Standard tables assume an average calorie expenditure of one calorie per minute. To find the MET you just need to divide the calories by the duration.

Example: "Bicycling, stationary, general", "20 minutes", "140 calories"
MET of "Bicycling, stationary, general" = 140 / 20 = 7

I know these calculations are somewhat tedious and in many cases the standard calorie calculations are close to correct. However, in some cases they can significantly over or under-calculate the calorie expenditure of activities and compromise your weight loss plan with daily miscalculations.

Mistake #3: Training with light weights and lots of reps

I have seen countless number of ladies come to the gym, get the lightest possible dumbbells, crank out some hundreds of reps and go home. Most often, these women do not get the results they want. The problem with this type of training is that it does not burn many "extra" calories unless you spend a considerable amount of time in the gym. Hefting Ken and Barbie weights in the gym has a MET value of 3, which means that it burns 3 times more calories than resting in bed. Almost anything you do during the day has a MET value of 1.2 to 2. Browsing the internet on your computer has a MET value of 1.5. Realize that almost anything you do during the day (average MET = 1.5) has about 50% overlap in calorie expenditure with training with very light weights (MET = 3). If you pump super light dumbbells in the gym, only about half of the calories burned are "additional".

Of course, you can burn a considerable amount of extra calories training with light weights but you have to really extend the duration of this type of training. Curling 5 pound dumbbells for 4 sets of 20 reps and chit-chatting for 20 minutes in the gym is not going to burn many extra calories.

Remember the rule: the less intensive the activity (smaller MET), the greater the calorie expenditure overlap with casual activities; the less intensive the activity, the more time you have to spend doing it to expend a good deal of extra calories. Always subtract a MET of 1 to 1.5 to arrive at the additional expended calories.

Mistake #4: Using "average person" calorie estimations

You can find all kinds of tables showing the calorie cost of different physical activities on the internet. These tables don't show your calorie expenditure. They actually tell you the calorie expenditure of an "average person". These tables assume you are an average person that burns one calorie per minute at rest. Yes, we covered this in the first part of the article and it needs repeating. Most men burn more than one calorie per minute and most smaller women burn less than one calorie per minute at rest. In reality, these standard tables overestimate the calorie expenditure of smaller people and underestimate the calorie expenditure of bigger than average people. Combine this with the common mistake of counting all burned calories as "additional calories" and you have a wide range of possible miscalculations.

Mistake #5: Going on very low calorie diets (VLCD)

Research has shown little to no difference in the weight loss rate of 1200 calorie diets and 800 calorie diets. The 1200 calorie threshold is the point where further calorie restriction does not yield faster results. Diets in the range of 800 to 1200 calories a day suppress the resting metabolic rate from the very first day and after some weeks on these diets, the metabolic rate has dropped by up to 20%. This metabolic drop is just a consequence of the calorie restriction factor; other factors such as the level of leanness may further depress the calorie expenditure.

A big percentage of the quick initial weight loss on a VLCD is water. VLCDs create an illusion of fast fat loss, while in reality most of the weight loss is water. It is hard to continue a very low calorie diet for a prolonged time because the harsh calorie restriction makes you hungrier than ever. People on VLCDs often lack energy and move very little. When you stop the diet, you are prone to instant overeating. Eating a very low calorie diet is the ticket to yo-yo dieting.

Instead of using very low calorie diets, I recommend diets with a mild calorie restriction and an emphasis on exercise. Overweight people who know what they are doing can employ VLCDs for a limited time. It is important to get enough vitamins and minerals from supplements, because such low calorie diets are woefully inadequate in nutrients. Water intake should be high.

Bodybuilders, powerlifters and athletes must stay away from very low calorie diets because the large calorie restriction causes a greater proportion of the weight loss to be muscle loss.

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Hristo Hristov is the owner of X3MSoftware, a company specializing in developing training and nutrition software. Hristo has a degree in Computer Science and passion for powerlifting. In his spare time, Hristo gives training and nutrition consultations. hristo@x3msoftware.com