What makes a meal healthy? Fresh foods. Unprocessed foods. Whole foods, such as whole grains. Making things at home as opposed to buying it ready to heat and eat. When things are made ahead and packaged, chemicals need to be added in order for the foods to remain fresh.
What is the healthiest form of vegetables? Well, fresh of course, and locally bought is even better. Next would be frozen. These have usually been processed the least. After this is canned, they do still have nutrition but not quite as much as the other forms.
I know - but my favorite vegetables are expensive in the winter. That is because it is out of season in your area and they need to be shipped in. And sometimes they don't taste as good even when you do buy fresh because of the amount of time they had to spend traveling. That is when i opt for frozen veggies. It is the next best option. The reasons I like frozen 1. they are easy to store and will not go bad as quickly as fresh if I decide to change my dinner plans, and 2. you can take out as much or as little as you want which is more difficult to do with a canned option.
Hope these tips helped! Have a great day!