i'm a fat guy and mostly not too worried about it - i'm pretty active and my weight/size hasn't kept me from achieving my goals. packing these damn bags is the closest i've come to dysphoria around my size.
there's just not quite enough space! everything's packed pretty tight and i haven't added in cooking gear (an alcohol stove stuffed in a little titanium mug) or food, or a change of clothes (optional). but, but, i can see how if i were a size or two smaller i could get a smaller sleeping bag and pad, my warm sleeping clothes could be a little smaller, etc, etc
none of this will actually stop me! there are bigger bags, i can add racks or cages, and i have the good fortune to be able to afford swapping things around. in a sense, it's nice that i haven't hit many other physical constraints in my life. just thinkin my thoughts and feelin my feelings
on the other hand, size euphoria is looking at expensive clothes and raingear and seeing only my size is left in stock at a steep discount