I've always been skinny - very skinny even - and could always eat whatever I wanted without gaining weight. I've also always - as far back as I can remember - suffered from depression and anxiety, and likely ADHD.
I stopped eating beef when I was about 12, for whatever reason, and went full-on vegetarian in my early 20s. After my worst depressive episode, and a trip to the ER after waking up in a full-blown panic attack, I started researching and came across books like Potatoes Not Prozac and the Sugar Addict series by Dr. Kathleen DesMaisons.
Eventually, after not eating beef for over 15 years, and after much agonizing, I went to the best butcher in town, bought myself a 10-oz ribeye, cooked it up in a pan with salt and pepper, steamed some kale on the side and went to town. I felt better after eating that steak than I had in years. I swear I got high off it. Best meal ever. Still get euphoric after a good steak.
That was about three years ago and since then I've been avoiding wheat/sugar with varying degrees of dedication but have struggled with being strict with myself. I think years of mental/emotional problems create habits which are very difficult to break.
This year I started a new job and with the stress of it I took to eating muffins/pastries every day - sugar makes the stress go away, for about 10 minutes. I also started having headaches every day, horrific mood swings, impenetrable brain fog and just generally feeling worthless. More research and I stumbled across Panu, Drs Eades, and Paleohacks.
I went 70% Paleo (I eat dairy, fruit, some nuts, and cheat too often) about three months ago and have been in awe of the changes I've noticed. My skin is clear and bright, my teeth are whiter, I'm happy, more social and able to think more clearly than I ever have. I'm still skinny, but the "problem spots" that we all have (even skinny girls) have shrunk - my "saddlebags" are significantly smaller, the waist of my jeans fits better (the muffin top is gone), my butt is smoother - without adding exercise or strength training - and I haven't lost any weight. My arms are stronger, I can lift more, and I don't get exhausted after carrying heavy things up stairs (it's part of my job).
I still struggle to keep more strictly Paleo as I love social eating and going out to restaurants, and I hate being the one to ask "do you have anything gluten-free?" I also live in Vancouver, which is a mecca for vegetarians/vegans, and most of my friends are at least veg, so to eat in almost complete opposition to them is alienating sometimes. It's also challenging after telling friends and family for years that I don't eat beef/meat that I now LOVE steak and crave meaty goodness at most meals. I can imagine the eyerolls I get from my mother-in-law when I'm not looking. Another benefit of Paleo, I've noticed though, is that it's much easier to turn down a muffin or a snack, without obsessing about it or needing to have it. Not easy, but easier, at least.
So, definitely not in it for the weight loss, but thrilled with changes in my body after coming to Paleo for what are basically mental health reasons. I have two younger brothers who are also super skinny, also suffer from depression, and are also going through a vegetarian phase. One lives with me and I'm doing my best to get good fats in to him without him noticing. My mom was also diagnosed with Hashimoto's thyroidisis a couple of years ago, is overweight and most likely diabetic - all things we've seen connected to gluten intolerance. I've been trying to pass good information on to her but she is not really interested and it's hard to give people what seems like weight loss advice when you're the "always skinny" one.