Breakfast cereals, muesli bars etc are not healthy at all as they contain a lot of sugar.
Same goes for juices in supermarkets. These are not fresh, often made of pulp and high in sugar. There are two ways of getting fresh juices : making by yourself or get them at a juice bar.
Same goes for snacks: if you want healthy ones, you have to make it by yourself. Don't know if your wife is onto baking but if not she can start a new hobby.