First of all, I also want to say

on realizing that this needs to be a lifestyle change and you decided you couldn't do that on the low carb choice. Not that others couldn't but so many times people seem to be afraid to say, "this just doesn't work for me" instead they think they've failed.
There is no food that is inherently "bad", it's all in how we incorporate it into our plans. I do however feel that chemicals and processed foods are not the best choices and we don't "need" them. Any natural food has good value for the calorie "buck".
Choices on snacks are totally a personal issue. I eat every 2-3 hours so there isn't much difference between a snack and a meal. I just make sure they are balanced with fat, protein and carb that way my blood sugar stays level and I don't have the problem of spikes that leave me "high" for a while and then lethargic (and hungry faster) when they drop. If I were to eat just a carb such as an apple, I would feel the spike of natural sugar much stronger. A choice for me may be to add a hard boiled egg to that apple or a slice of whole grain sprouted bread with natural almond butter. (fat, protein and carb)
There's nothing "wrong" with mayo, especially if you can get some natural or make it yourself. It's just that it's all fat and a lot of people would rather spend those calories on something else, especially if it's a low calorie plan. I choose to have flax oil/seed, nuts, nut butters as my main fats because they either have the healthy omega 3's that I need or the seed, nuts and butters have protien, fiber and just taste great!
Don't worry, you're on the right track!
