Flexible Dieting IIFYM for Obese Individuals
Flexible Dieting is a great method for losing weight and has helped thousands achieve both their weight loss and fitness goals.
But, for obese individuals (in this case, those with 50+ pounds to lose) the process and TDEE/macro formulas aren’t always cut and dry.
The Metabolic Needs of Fat Tissue
The cells in the body that store fat are a living tissue and do require nutrients and a blood supply, but the energy they require to maintain themselves is a fraction of the energy required for active bodily tissues like muscle and nervous tissue.
Flexible dieting uses widely trusted resting metabolism equations to factor a person’s TDEE (total daily energy expenditure) and macro amounts but one of the key factors in these equations is a person’s body weight.
However, if more than 50 pounds of that weight is from fat tissue, it can skew the results of the equation and cause the person’s TDEE to be estimated too high.
Fat tissue simply does not require the same amount of energy as other tissues and therefore, must be considered carefully when estimating a safe and effective weight loss TDEE.
According to research that looked at the resting energy expenditure of different bodily tissues, adipose tissue (fat) burns just 2 calories per pound per day. So someone with 75 pounds of fat would only require 150 calories a day to maintain that fat tissue. On the other hand, resting muscle burns 6 calories per pound and nervous tissue 109 calories per pound per day.
Here’s a great chart that summarizes different tissues’ and organs’ energy use.
Where IIFYM Formulas Fall Short
Hopefully, you can now begin to see how the same formula will not work for everyone since standard formulas were designed for those with what is considered an average body composition for a man or a woman.
A person that is 180 pounds with a lean mass of 170 will have a different TDEE than someone who is 180 pounds with a lean mass of just 120 pounds.
The 170 pounds of lean mass person requires more energy because they have more lean muscle mass. The person with 60 pounds of excess fat requires less energy.
Most standard flexible dieting formulas do not take this into consideration when determining a person’s REE or TDEE. 180 pounds is factored the same way no matter what the composition of those 180 pounds.
For those with less than 50 pounds to lose, the formula still is effective because the body composition differences would be smaller, but for those with 75, 100, or even 200 pounds to lose, this fat tissue weight should be factored into the equation.
Consider Lean Body Mass
First figuring out your lean body mass when calculating your TDEE and macros can help create a more accurate picture of the energy your body actually requires while at rest, which can make the difference between success and frustration for those with significant weight to lose.
You can get a good estimate of this by using this body fat percentage tool here.
Now that you know your lean body mass, you can use that as the basis for a macro and TDEE calculation.
Here’s a comparison that visualizes the difference in the macros for an obese individual using both their true body weight and their lean body mass.
Here we have a 30-year-old male who is 5’10” and 270 pounds. He has a lean body mass estimated at 204 pounds. He walks for about an hour daily so this would be classified as light activity and also factored into the equation.
As you can see, there is more than a 300 calorie difference in the two sets of results and this could make a big difference in whether or not Flexible Dieting would prove successful or not.
Are we to ignore fat tissue all together?
No, fat tissue does burn calories as shown in the above chart and this isn’t completely being ignored by using lean body mass. In our example, the ideal body weight for the guy shown is about 170 pounds. Therefore, there are still 34 extra pounds calculated in the formula to account for the calories his fat tissue would be burning.
If a person’s lean mass calculated close to their ideal body weight then I suggest adding around 25-50 pounds to help account for their fat tissue metabolism.
It’s a bit complicated and that’s why some personal coaching is beneficial for those with a considerable amount of excess fat to lose.
Calorie Level Disappointment
Many people with significant weight to lose who use our calculator get excited when they see how many calories it tells them that they can eat for weight loss.
But when they become a coaching client of mine, they become disappointed when I formulate their macros for them based on the adjustment for their excess fat tissue.
While the calorie levels are lower than what was initially expected, flexible dieting still allows for the eating of much more food than most popular diet plans.
For example, Nutrisystem only allows males to eat about 1500 calories a day regardless of exercise or body weight.
Also with Flexible Dieting IIFYM, the more you exercise, the more you can eat since this method is always striving to maintain a safe calorie deficit of 20%. In the example above, if our guy began to exercise more and enough to jump to the “moderate” category, he could then eat 2348 calories per day.
Flexible Dieting Should Be Individualized For Obese Individuals
With flexible dieting there isn’t a one size fits all calculation and macros should be formulated with an individual’s unique stats and body composition in mind.
While calculators can give the average person a good starting point, for many people, a more individualized approach to calculating macros and TDEE is needed.
If you have more than 50+ pound to lose, you’ll have the best results if you use a more tailored set of macros. I can do this for you as part of the coaching plan we offer or you can use the information in this article to calculate your own macros that are more conducive for reaching your weight loss goals.
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- McClave SA, Snider HL. Dissecting the energy needs of the body. Curr Opin Clin Nutr Metab Care. (2001) 4(2):143-7 abstract link
- Leibel, R. L., & Hirsch, J. (1984). Diminished energy requirements in reduced-obese patients. Metabolism, 33(2), 164-170. abstract link