Also a very bad assumption, but that I see a lot, is that increasing or decreased absorption and use of one nutrient affect all others equally...<p>I have Hashimoto&#x27;s Disease, and people tell me that I should just eat less, to stop gaining weight randomly...<p>The problem is that I absorb calories too easily, and use them too slow, while I have problems absorbing everything else (and using everything else).<p>The result is that I need a very high protein and vitamin intake (medics even told me to use some supplements, for example it has been years that I am taking vitamin D in the maximum &quot;safe&quot; known dosage, and my blood levels are still in the &quot;dangerously low&quot; level) to keep my body barely working properly (Barely because I struggle to keep lean mass, not only in muscles, but also hair, nails, skin... my hair is constantly falling, nails break for no reason, and sometimes layers of my skin start to peel off).<p>But the amount of resources I need to keep my body working, has in themselves more calories than my body uses...<p>So my choices are: don&#x27;t eat and get rapidly worsening health, or eat and get fat.