I'm not even sure how to begin this one as it's still a work in progress at our house. We are slowly moving from being a family that sustains itself nutritionally from the freezer and carbonated cans of soda to one who eats whole, healthy foods.
My first tip in eating healthier is make a meal plan! I spend a large percentage less at the store if I have a meal plan and a list.
Second tip is never, ever, ever go hungry or stressed. The later of the two effects my shopping trips more. This is how my cart ends up with mostly produce and a box of twinkies (there's something to be said when the nation goes into withdrawal at the removal of this off the shelves but that is a different story), two cases of soda, a bag of chips, the lovely dip to accompany it, and frozen pizzas.
Third, actually read the labels. Though somethings this doesn't always help because nutritional labeling in the United States is a farce. "Natural" doesn't mean ingredients that only grow in nature. It can mean proteins and fillers derived from natural growing things by processing them. Organic doesn't mean it is 100% organic either. It's only "organic" up to a certain percent. This means that the produce or product wasn't completely grown or made without man made chemicals or genetic intervention. You can only be certain that it is what it is if it says 100% USDA Certified Organic or if you physically meet with the farmer or gardener that is producing the product.
Fourth, look at the numbers on your produce. Produce that begins with a 4 is conventionally grown with man made intervention such as synthetic or natural fertilizers and pesticides. If it starts with an 8, buyer beware, it is a Genetically Modified Organisms, or GMOs. This means that the genes of the plant have been modified to make them resistant to certain strains or bacteria, ward off certain bugs, and assist them to sustain themselves in the mono culture environment they are unnaturally put in. They don't only use the genes from other produce to genetically modify the GMO produce, they also use animal genes. In high school our science teacher thought us our lesson on GMO's by giving an example about tomatoes being genetically modified with the genes of a wild Alaskan fish so they they would not freeze during transport. Most of our produce in the super market travels over 1,000 miles before it hits our stores. Only if it starts with a 9 is it grown Organically without any synthetic, chemical, chromosomal alternations.
Fifth, I try to only shop the perimeter of our grocery store. Minus the ice cream section, this is the healthier part of the store. It's your fruits, veggies, nuts, rice cakes, popcorn, dried fruits, 100% juices, dairy, and meat. The only exceptions that I go into the center isles of the store for are, casein free, gluten free, sugar free fruit snacks for the boys, and grain flours, pastas, oils, and spices. This helps me completely bypass all the processed products that can live on the shelves for upwards of decades past the "sell by" date. After educating myself on food and our body, it completely disgusts me thinking about food that can sit out on a shelf for years because of chemicals and synthetic fillers that persevere it. I do however have no problem with homegrown and canned foods. This is an entirely different entity and nothing synthetic is used in the process. There is just something disgusting about altering things that aren't supposed to go into your body to make a food taste "good" or to be "low fat," "low sugar," "cholesterol free."
We try to buy fresh, fresh, fresh, whole, unprocessed ingredients.