I find that one healthy food brand that I use is Kashi. They have cereals and cereal bars, etc. They use whole grains, have low fat (no saturated fat), high fiber and low sodium. If you like Frosted Mini-Shredded Wheats brand cereal, Kashi's Island Vanilla organic whole wheat cereal is wonderful.
It has 190 calories, only 10 from fat, but the high fiber makes the caloric intake less daunting because with fiber, the food doesn't "stay around" in your digestive system a long time. I don't drink cow's milk, but soy milk, almond milk or another alternative, along with fresh fruit (I like it especially with blueberries) makes for a great breakfast or a wholesome, filling, taste-full and satisfying snack. I like that it uses evaporated cane juice and syrup rather than high fructose corn syrup. I am eating only plant based foods (no dairy or meat) and it has its challenges, but this breakfast is a keeper.
Kashi has a wide variety of breakfast foods and snacks that offer different flavors as well, all organic, using whole wheat and even multi-grain.
You note that the basis of your question is a project that is asking for brand names that produce "healthy" foods. Many of the responses note that the healthiest foods don't come from any brand, but use fresh ingredients prepared at home so you can control additives.
Would it be possible to frame your presentation in terms of alternatives to brand name products? Is it more important to eat the healthiest foods or to purchase the commercially produced foods that have the fewest nutritional problems?
There are those who would also argue that the "healthiest" way to eat (for your body and for the earth) is to buy things locally and naturally grown, rather than mass produced, mass marketed, and shipped across the country.
My family enjoys Muir Glen products -- canned fruits and vegetables. Van's makes excellent frozen waffles that my kids like better than other more famous brands. We also drink organic milk -- we prefer the milk of a local producer, Oberweis, but will also buy other brands as they are available such as Organic Valley. I also try to buy only grass fed beef such as the Tall Grass Beef brand. Many manufacturers produce traditional and organic or "healthier" versions of their products.
Though I have not done any kind of extensive research on this, it does seem to me that Kashi makes some of the best products in terms of health food, especially cereals and granolas.
I think the biggest thing for you to think about is not to eat processed foods and to think about cooking from scratch. It is incredible the amount of junk that pre-cooked, processed foods have in them. It is so much healthier cooking from raw ingredients, and fun too! You also find you have many more options and the chance to be creative, so go and dig out that old dusty recipe book and start remaking some of those old classics! However, apart from this advice, any of the products listed in #2 and #3 are good.
Perhaps more important than the label is the consumer's ability to read the labels and choose foods which are low in fat, sodium, and artificial substances such as high fructose corn syrup and preservatives. High fat, sugar, and carbohydrates should not be eaten often nor in high quantities.
I prefer fresh veggies and fruits, low-fat and low salt meats, and multigrain breads. Whole wheat pastas and brown rice also frequent our table.
There are lots and lots of brands that have multi-grain and whole wheat offerings.
For example, Nabisco makes Wheat Thins that are whole wheat along with Wheat Thins that are just made from regular white flour.
Another example is Barilla, a pasta maker. They make regular pasta, but you can also get things like whole wheat spaghetti from them. It has about 3 times the fiber per serving of regular pasta.
I imagine that most major brands these days sell some products that are whole wheat or multigrain.
This is more like a discussion topic, but I can tell you that, as a dieter for over a decade, the healthiest brands of foods have three things in common:
1. They are freshly made or not previously processed.
2. They have no added preservatives.
3. They promote healthy living and other forms of expanding your healthy diet -ASIDE FROM their product.
Among some favorites are Trader Joe's, Amy's, Eden's Own, Steaz, and Ezekiel are some that I would personally recommend.