As a personal chef, I often get calls from people who were recently diagnosed with an illness and have to change their diets. It can be so overwhelming, in the beginning, to have to break old habits and not know where to start. My very first client had been diagnosed with Celiac disease. This was several years ago, before labels clearly stated whether the product contained wheat, for example. I made many phone calls from the grocery store in those days, to find out whether a product was safe for my client to eat. I now consider myself very well versed on which gluten free pastas are good, and which ones are pasty and flavorless! There are some really good ones out now, and much more readily available than they used to be!
More often than not, people with special diets are much easier to cook for than they might anticipate at first. I focus on the foods they can eat, instead of trying to substitute the foods that are off limits now. Usually, it goes hand in hand with the way I cool most often. Healthy, lean meats, full of protein. Lots of fresh vegetables, roasted, tossed with fresh herbs or toasted nuts.

I have cooked for all kinds of special diets. I have cooked for people with diabetes, Lupus, high blood pressure, Huntingtons Disease, Parkinsons, Alzheimers, cancer, etc.
It is so rewarding to cook for people with sensitivities, allergies, or illnesses, and have them really enjoy eating, as well as helping them recover. When I cook flavorful food with lots of variety, it makes my clients mealtimes a lot more enjoyable!