There are a number of reasons that I choose to avoid animal products, gluten, and soy in many of my recipes. To be clear, I do not follow a vegan, gluten free, or soy free diet. (Although I did have to omit all soy for some time.) The reason that I choose to share these types of recipes is because I think that thinking outside the box leads to great choices nutritionally, and it's difficult for people who have grown up in a traditional US household to envision cooking without these ingredients. Yet there are so many great ingredients and recipes out there! Some of my reasoning on each of these choices are shared below.
Vegan: My fiancé and I made a gradual transition to vegetarianism after watching the documentary Forks Over Knives. I think that anyone who plans to be vegetarian long term should have a good arsenal of vegan recipes up their sleeves. Replacing meat with cheese and eggs one for one doesn't really improve your diet nutritionally or make a huge difference the lives of animals. Finding vegan recipes comprised of a variety of whole food ingredients to make up the bulk of your diet will ensure that you're getting all of the micronutrients you need.
Soy Free: Most of my recipes are soy free. As I mentioned, I had trouble digesting soy for about a year. I have a theory that this was a result of over exposure: in the year before having to give up soy, soy was my most frequently consumed food. When I decided to give it up, I found that I was eating so much soy that everything had to change. After a few rounds of probiotics and year of abstinence I can occasionally eat soy. However, between my past experience and the potential of soy to act as an estrogen mimic, I try to avoid regular consumption.
Gluten Free: My roommate, who is also my best friend, is sensitive to gluten. This is obviously a huge motivator for me, as cooking and sharing meals is a highly social activity for me and that right there would be enough of a reason to motivate me to cook this way. I also noticed that more and more people are becoming allergic to the foods we eat every day so I think focusing on consuming a variety of grains is key to optimal health. Variety is the spice of life!