This is an astonishingly simple, yet deeply complex question. To start simple, a healthy diet is one comprised of fresh foods consumed in appropriate quantities. Simple, right?!
Here is where the complexities start:
1) it is almost impossible to find “fresh food” the way our bodies want it
2) there is debate that some naturally occurring, fresh foods are not as good as others
3) appropriate quantities can be difficult to define and are specific to each individual
Let’s clear up some of the confusion. Our genetics are designed for the fuel that was available to our ancestors hundreds of years ago. Shortly after WWII, highly processed and sugary foods entered our lifestyles. When “fresh food” is being referred to, think vegetables, fruits, nuts, naturally occurring oils, meats from live animals, grains that grow from the ground. The not so fresh foods are salad dressings, frozen pizzas, fast food restaurants, American cheese, etc. The list would be endless, just like the food items that line most of the inner aisles at the grocery store.
So how can you possibly eat fresh, when fresh is so hard to come by?
1) stick to the outer edges of the grocery store. This is a common tip, and an excellent one worth repeating. Start with a variety of fresh, leafy greens. Add to it some other colorful veggies to cook such as squash, zucchini, and green beans. Limit fruit, but choose 1 or 2 varieties to have on hand. Then select fresh cuts of fish, poultry, and lean red meat. Grab some 100% egg whites and eggs on your way to low-fat milk and greek yogurt. Skip to the grain aisle just long enough to find quinoa, barley, wild rice, and oats.
2) find fresh produce locally. Once you try a juicy tomato fresh from a garden, or have an omelet made from free-range eggs, you may never want to buy these in a typical grocery store ever again. Find a local farmer’s market or individual farmer to make your produce, egg, and meat purchases.
3) change your idea of a snack. Snacks don’t have to be cookies and milk, or crackers and cheese, or a granola bar and fruit snacks. Eat things like celery and natural nut butter, broccoli and hummus, oats with cinnamon, slices of fresh turkey.
To address point #2 from the top, YES, some fresh foods are better than others. For example, if you are trying to lose weight, certain high-glycemic fruits, vegetables, and grains can slow down your weight loss. Some people struggle with eating grains containing gluten. If you have questions about what foods are best for you, seek personal advice from a fitness professional.
Portions are best determined by your body size and activity level. For some great calculators, try theses websites: