Flexible Dieting IIFYM for Obese Individuals

Flexible Dieting IIFYM for the obese

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.

Here’s why…

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.

iifym obese calculations

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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    References:

  • 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

16 Comments

  1. Bob 2 weeks ago

    When doing macros, do you back out fiber from Carbs or are they counted along with all the carbs.

    Reply
    • Ted Kallmyer 2 weeks ago

      Hi Bob, Although not all fiber is digestible and provides energy, it is easier to use total carbs for tracking purposes. Doing this gives you a little “buffer” in case you go over on your carbs.

      Reply
  2. Lexa 3 weeks ago

    This is confusing for me how would you recommend using the calculator who is a lowish normal weight for their height but has an obese percentage of body fat?

    Reply
    • Ted Kallmyer 2 weeks ago

      Hi Lexa, I would guess that your body fat percentage isn’t calculated correctly. You are not obese. Just use the normal calculator settings.

      Reply
  3. Nat 4 months ago

    Nat

    Reply
  4. Doro 8 months ago

    This is SO hard – and time consuming. As a mathematical moron I just want to know what to do. Period. And I’m vegan. I don’t see any provisions for vegans. Are there any?

    Reply
    • Ted 8 months ago

      Hi Doro, We have a calculator that does the calculations for you. There are no provisions for vegans because there’s no required or forbidden foods. Vegans simply eat the amount of protein, carbs, and fat that is recommended. Here’s the calculator link: https://healthyeater.com/flexible-dieting-calculator You then may have to make adjustments if you have a lot of fat to lose.

      Reply
      • Doro 8 months ago

        Many thanks for your prompt reply. I’ve followed the link, and think I’ve “got” it now. Thanks again.

        Reply
  5. inga 11 months ago

    Hey can i please get some help
    Im 23, 160cm, 80.8kgs, i do crossfit 4- 5xs a week, i would like too loose atleast 1kg per week or 0.5 so whats that calories i should be eating perday to acheive this and how much grams of carbs, protein and fat per 3meals would i be having thanks.

    Reply
  6. Jenna

    I’m confused, How should a calculate it if I have like a little over 60 pounds to lose? I’ve been eating very unhealthy foods for a while so I def have high body fat

    Reply
    • Ted

      Hi Jenna, You can use the standard formula but your macros won’t be fine tuned for the best results because of the fat tissue. You’ll still likely get results but they’ll be slower. I consider a number of factors when calculating for my coaching clients with 50+ pounds to lose and it’s highly individualized.

      Reply
  7. Katherine

    Hi I’m a 27 yo female that weighs 151 lbs with a lean mass of 102 lbs, 33 %. I’ve been struggling to lose the excess fat for months now. I workout 6 days a week lifting weights and cardio a few days a week also. Should I follow the lean mass macro calculations? It came up with 1690 Cals. 125 pro, 192 carbs, and 47 fats. And since I have a high body fat % should I leave the protein level to normal? I have been eating my grams in body weigh. Help!

    Reply
    • Ted

      Hi Katherine, sorry for your frustration it can be challenging to get things right. The lean mass setting is really only appropriate for those with a low body fat percentage or a high proportion of lean mass. I think the standard formula is the one you want. And yes, you don’t need 151 grams of protein so you can cut that back.

      Reply
  8. eva colarusso

    am i supposed to put in my actual weight or the weight for my lean body mass?

    Reply
    • Ted

      If you’re classified as obese it can be a little more complicated. We have to consider lean body mass but also account for the metabolism of the fat tissue and add that back in. I always recommend personal coaching for such situations. https://healthyeater.com/personal-coaching

      Reply