18 Comments
User's avatar
Unirt's avatar

Like others here, I'd be delighted to eat as much calories as the tool suggests I should (2800 for a tall and somewhat muscular woman). Yet, of course, I'd go very fat very fast if I actually did that (have tried). With a metabolic adjustment of 0.75x I get to the figure that some other online calculators tell me I should consume to stay at the same weight (below 2000, which feels like A Diet).

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Experimental Fat Loss's avatar

In my experience, most of the online calculators vastly underestimate a "normal" TDEE compared to the actual real-world measurements like these.

That said, this dataset can only give you statistics. They're currently not sure why some people are at 0.75x and others at 1.0x or 1.35x. Some crazy endurance athletes are even higher, and that kinda makes sense, but there's quite a bit of variance around the 1.0x..

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Dennis Nehrenheim M.Sc.'s avatar

This is great. My result would be around 3500kcal, which would be a dream....I would mean I am in a deficit almost 100% of days. But now I am extremely puzzled why I lost only 3kg of body mass when restricting calories to 1800kcal per day while working out hard (but not adjusting for exercise calories) for three months. Just doesn't make sense....even in the traditional model I should have lost 6-8kg and according to this model I should have lost way over 10kg with that regime. How would you possibly explain that? A very slow metabolism? Loosing muscle mass then building it up again because I was in a way too big deficit?

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Experimental Fat Loss's avatar

Well I would explain it by "that's not actually how the metabolism works" :) Restricting by x kcal doesn't usually just result in a linear fat loss of that many calories per day, although it does seem to work in some people, some of the time, for some period.

As a comparison, I allegedly burn 4,600kcal/day and I measured my intake at 2,890kcal/day and I didn't lose any weight. Even if we assumed the 4,600 was measured wrong and I'm really "only" at my expected average 3,200kcal/day, I should've lost weight.

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Scott's avatar

Estimated 3200/day for me, which is likely too much. I did have the thought that it is likely easier to get fat if you need fewer calories than average for, ah, mysterious reasons. Fist bump to Unirt to making me realize that.

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Experimental Fat Loss's avatar

Yea if only we knew what the mysterious reasons were :)

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JS's avatar

This is awesome, thank you so much! With the benefit of owning a caliper, tracking calories for almost a decade (I know, I am old!) and having my weight stay within +- 5 lbs for the past 5 years, your calculator with a metabolic adjustment of -0.8 is spot-on. Now as others have mentioned, I could restrict calories by 20% and my weight would not budge, which means my metabolism slows down to match the intake. It would be fantastic if each person could find that "sweet spot", ain't easy to do.

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Experimental Fat Loss's avatar

Yea it seems that everybody has a different "power band" within the range, if you will. Would be cool to measure & map that out lol. But even this data is brand new, the study is only from 2021. So we're just starting to even map this landscape.

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Adam's avatar

This is mind blowing to me. I've put my fat free mass in at 80kg and it comes back at about 3600 calories. Are you saying I should be eating 3600 calories every day!? Man everyone should see this. I think you said in a previous article that calories in, calories out doesn't really work. Really beginning to think this is true.

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Experimental Fat Loss's avatar

80kg is extremely high fat free mass, I'm at 70kg as a somewhat muscular guy @ 6'1. Is that an estimate or did you calculate/measure it?

The tool is more descriptive than prescriptive. It can't tell you you "should" eat 3,600kcal/day. It's telling you that the average person with 80kg of FFM is burning 3,600kcal/day.

You might be higher or lower than that. But 3,600 isn't actually that crazy, I'm eating between 2,800-3,300 and that's just "normal" for my 70kg of FFM. If you have 10kg of lean mass on me, I would expect you to burn that much. I've actually eaten around 4,000kcal/day before without gaining weight.

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Adam's avatar

It was more of an estimate. Would say probably 70kg and below. But yeah I get what you're saying. How would you work out your body fat percentage?

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Experimental Fat Loss's avatar

You could get a DEXA scan, and some "smart" bathroom scales can estimate it. You could also just take your total weight and guesstimate your body fat% and then subtract that.

E.g. I was 221lbs this morning, and I know I'm around 30-31% body fat (from DEXA but you could guess from e.g. pictures). If I subtract 30-31% from 221lbs, I arrive at around 152-154lbs of fat free mass, which is about 70kg.

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Adam's avatar

Very helpful. Will try this. Thanks

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JS's avatar

I have a simple skinfold caliper (You can buy one on Amazon) that is fairly accurate. I have the Accu-Measure brand but there are literally hundreds to choose from.

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Experimental Fat Loss's avatar

I've heard you have to learn to use the calipers correctly to be accurate, so I've never tried them.

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JS's avatar

Locate your belly button. Locate your right (or left) hip bone. Place the caliper half-way. Grab the skin, pull gently outwards. Place the caliper, close down, look at the measurement. It gives you a range, which for me is good enough!

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Julian's avatar

I'm a little concerned that the overlaid graph (which you said you based your upper/lower end lines on) has an x-axis of 0-200lbs overlaid over 0-100kg, which is actually 0-220lbs. Is this just an issue with that specific image or did this affect your estimated bounds?

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Experimental Fat Loss's avatar

That's a good point, I did actually switch it to kg for this and just forgot to do that when I just took the screenshot. I'll fix it and you can see it more clearly!

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