Is going GF & DF like going kosher?
Most of us didn't grow up staying far, far away from gluten and dairy. I had no idea until a week ago that even holding gluten and dairy products physically pains my body. And, then again, many people didn't grow up keeping kosher, either.
I grew up with neither--eating non-kosher ice cream brands, non-fish gelatin marshmellows, clams in tartar sauce, bacon-lettuce-and no tomato sandwiches. Lucky for me, I never liked cheese burgers, ham, or most shellfish. Giving up the 'forbidden foods' wasn't as taxing for me as it is for some.
And, I still love real bread sandwiches, glutenous doughnuts, bagels with dairy-cream cheese.. the works. They are things that I'm giving up for a reason--I could, of course, continue to eat gluten and dairy, it would probably just kill me. And, if it didn't kill me, it would lead my body to constantly be hurting and working at less than 100%. Same with kashrut, but with a spiritual effect. If you put a shrimp in my mouth, my neshama won't do well with it.
Shomer Kashrut: I started keeping kosher years ago for a number of reasons. My observance of kashrut has grown drastically--from when I didn't know that non-kosher cheese couldn't be eaten to now, when, of course, I can't touch cheese--no matter what the hekscher. I partially started looking into kashrut because someone in my family had experienced an eating disorder and I was trying to process my relationship with food, and partially because I picked up the Torah one day. I read. It said 'no shellfish,' so I quit those. I later learned, from rabbinic sources, that caesar-with-cheese-and-chicken was a no-no, and gave that up, as well. Non-kosher meat became a thing of the past, and I took up vegetarianism because there simply was no kosher meat that I could get access to. Slowly, more of my time become occupied with kashrut thoughts. 'Is this kosher, and to what degree?' 'Which products don't require a kosher-label?'
Similarities: In both cases, I'm deny myself things my tongue craves. I have to constantly remind myself that kashrut builds character, and that what I want (i.e. ice cream right after a burger) is only about what I want--not what I need, and not what my soul needs. It's about planning ahead, you can't go anywhere and just expect to pick up some food, you have to think ahead of time. Want beef? Yup, that will be a minimum 2-hour drive. Want pure oat flour to make bread? Yes, that will be a 30-minute drive. You get over it, and you learn to plan your time better--even if it's not what you'd rather be doing.
However, with keeping kosher (unless you are super-machmir) you can walk into a gas-station while traveling, pick up most sodas, chips, pretzels, and a wide variety of candies, and you're fine. Being gluten-free and dairy-free means that there is very little left to consume in terms of junky fast food. When I had a 2-hour drive the other day, I didn't prepare ahead of time. The only thing that I could find where potato chips, so I picked up a bag and continued on my way.