&gt; I would like to see this in reputable studies, because everything I have read on the subject rejects the hypothesis that there is a physiological change in energy usage as a result of lowered intake. In fact, it a) doesn&#x27;t make any sense since fat is supposed to be a store of energy for lean times and b) if the body could function at its current level on less energy, it would.<p>This is still talking about near starvation mode.  People who stop menstruating and who grow lanugo are doing stuff that reduces their need for energy.<p>(I&#x27;m not sure it&#x27;s accurate even for this extreme state though.  Re-feeding is risky, but I don&#x27;t know if &quot;starvation mode&quot; is part of the cause of that risk.)