Impact of extreme obesity on TDEE?

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  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    edited July 2017
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    try2again wrote: »
    Do you have links to sources/studies that discuss this?

    Sure! Pubmed is full of studies on/around this.

    Background activity burn can be modelled pretty well as just a multiplier on BMR (for example, sedentary NEAT is typically 1.2x BMR). Intentional exercise is calculated on its own, and added to BMR+NEAT. We have good understanding on how to get good numbers for exercise burn.

    So at the core, what we're talking about is whether BMR tracks better with Fat Free Mass (ie Katch-Mcardle equation) or with total body weight (many options, typically Harris-Benedict for online calculators). Because the key to accurate TDEE is getting BMR and activity level as accurate as possible.

    Here are a couple of links - but as I mentioned above, there are so many of these you could spend the rest of your life trying to read them all! :)

    https://www.ncbi.nlm.nih.gov/pubmed/27641466
    PubMed wrote:
    The Harris-Benedict equation provided 40 and 47·5 % accurate predictions before and after therapy, respectively. The FAO equation provided 35 and 47·5 % accurate predictions. However, the Bland-Altman analysis did not show good agreement between these equations and indirect calorimetry. Therefore, the Harris-Benedict and FAO/WHO/UNU equations should be used with caution for obese women.

    https://www.ncbi.nlm.nih.gov/pubmed/28749749
    PubMed wrote:
    The new specific equation based on FFM was generated as follows: REE = 451.722 + (23.202 * FFM)...Previously developed predictive equations mostly provided unaccurate and biased estimates of REE. However, the new predictive equations allow clinicians to estimate REE in an obese children and adolescents with sufficient and acceptable accuracy.

    I also want to reiterate that any method can lead to success, if tracking is diligent. Because diligent tracking of intake and activity *will* reveal accurate TDEE and NEAT for anyone. It's a PITA, I know, but 60 days of diligence can lead to pretty profound insights about how our bodies are actually working.

    EDIT: Just wanted to add a comment about rapid weight loss often seen with successful obese dieters. There is mounting evidence that high levels of adipose fat cause proportional increases in water retention in the non-fat parts of the body. So the heavier you are, the more water weight you will drop in caloric deficit, even apart from the usual glycogen depletion etc. Which means weight loss in early stages of de-obesing can appear to be larger than the caloric deficit would predict.





  • try2again
    try2again Posts: 3,562 Member
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    Thank you, @Mr_Knight -that's exactly what I was after. I will definitely look into it when I have more time.

    I do believe that accurate tracking is the only way to know the true story. But I'm also very concerned about encouraging people who may already be inclined to pursue extremes. As I've mentioned in other comments, I feel it's important to think in terms of long-term sustainability. I guess I'd rather see people error on the more generous side and adjust downward only if necessary, but I realize that's not many people's preferred way of doing things.
  • fdebb
    fdebb Posts: 8 Member
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    I'm so confused. Started mfp about a week ago. It says my calorie intake should be1420. I'm 46. 5'3 and 292 pounds, sedentary. I have not even been able to eat that many calories, idk if I should be eating that to lose weight?
  • kshama2001
    kshama2001 Posts: 27,898 Member
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    fdebb wrote: »
    I'm so confused. Started mfp about a week ago. It says my calorie intake should be1420. I'm 46. 5'3 and 292 pounds, sedentary. I have not even been able to eat that many calories, idk if I should be eating that to lose weight?

    Heya - you should really start a new thread with this question. When you do, change your Diary Sharing settings to Public: http://www.myfitnesspal.com/account/diary_settings because there are common errors that lead people to eat more than they think they are.

    But yes, someone with your stats can definitely lose weight eating 1420 calories.
  • try2again
    try2again Posts: 3,562 Member
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    fdebb wrote: »
    I'm so confused. Started mfp about a week ago. It says my calorie intake should be1420. I'm 46. 5'3 and 292 pounds, sedentary. I have not even been able to eat that many calories, idk if I should be eating that to lose weight?

    Please stick with your MFP recommendation unless your results after a month or so don't yield the desired weekly weight loss average. Make sure your logging is accurate, but do not be afraid to eat the full calorie amount. You are capable of eating the full amount of calories. Please consider the "most helpful" posts at the top of the general diet & weight loss section:

    http://community.myfitnesspal.com/en/discussion/10300319/most-helpful-posts-general-diet-and-weight-loss-help-must-reads#latest

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