I do wonder how much of this is cherry picked. Look my food bill is high. I have a family full of food allergens. One kid who is allergic to peanuts, egg, and cannot tolerate lactose. A wife who cannot have gluten or peanuts, a daughter who also needs to avoid gluten, and a boy who can eat anything. A loaf of bread for my wife/daughter is $7-9, and it isn't particularly large. A loaf of white bread is typically $2-3 and is double the size, but is also loaded with a bunch of bullshit and preservatives. Due to a genetic mutation, enriched wheat products are a no-go in my home as well. So I found Izzo sourdough bread which is about $4-5 for a load, can grow mold, and isn't loaded with preservatives and that works for us. So, while a typical family might only spend $3 on bread per week, I spend about $12.
Yes, there is a convenience price. I tend to buy blocks of cheese and shred it myself. My kids don't really do well with the dyes in candy, so I buy more expensive candy (giggles instead of skittles) to give them a treat. Non-dairy ice cream is $4-6 a pint and is not always available with fewer alternatives. Regular cow-milk, is $4-6 for a gallon.