Maximum rate of lipolysis (30cal/lb/day)?

Hi, I heard this from two places now, 1) Ted Naiman on the high intensity health podcast and 2) in a question on one of Q and A on a low carb down under conference. “The maximum fat liberation rate is 30 calories per pound of body fat per day” I’ve looked for further sources, but can’t find anything. Has anyone else heard this or have any other sources? I find the idea interesting, but could also be fasting bro-science... If I am 200lb at 15% then this would indicate 30lbs fat @ 30 cals/day = 900cals. So maybe after liver and glycogen (400x4 = 1600) taken into account fasting longer than 48hrs is no good...? There’s got to be so many variables, like adrenaline hormone levels etc to make a simple rule of thumb like this, which makes me think it’s more bro than science. Would love to hear any thoughts or sources on this?

Answer

It comes from this study: https://pubmed.ncbi.nlm.nih.gov/15615615/

Which was basically doing a regression on the Keys Minnesota Starvation Experiment data. It’s probably different in a fat free mass sparing regime like fasting (I think they mention that in the paper). Though there is probably a limit to fat mobilization even in fasting, but it’s probably higher.

EDIT: 290kJ/kg·d = \~31Cal/lb·d

Answer

The hormonal “slowing down” of lipolysis only appears with allready low BF% people (10-%) other than that you can check upon fasting clinics all over the fat loss especially in obese when the metabolic shift occurs is way more than that (considering the loss of fat they have) that being sad I still belive its more than basic thermodinamic when it comes to human body or should I say the rate of which the laws of it express is different from individual to individual as far as I Have observed.

Answer

Lyle McDonald wrote about this about two decades or so ago:

https://anabolicminds.com/community/threads/determining-the-maximum-dietary-deficit-for-fat-loss.54527/

Not sure if he still believes in this, as he regularly updates his material, but I found that this figure was largely attributed to him and his interpretations of the PubMed study linked by the previous commenter