If you don’t already know what’s slowing you down, it may be in what you eat. Groceries stores can quickly become the enemy when they sell you pesticide covered fruits and vegetables, genetically modified organisms, and synthetically produced goods full of chemicals for preservatives. Check out this list of things you should always avoid:

1. Nonorganic Strawberries

Robert Kenner, director of Food Inc. and founder of FixFood.org

The Problem: While filming Food Inc., Kenner says he wanted to film strawberry farmers applying pesticides to their fields. “The workers wear these suits to protect themselves from the dozens and dozens of known dangerous pesticides applied to strawberries,” he says. “When I saw this, I thought to myself, if this is how berries are grown, I don’t really want to eat them anymore. I haven’t been able to eat a nonorganic strawberry ever since.” Unfortunately, for the food-concerned public, he wasn’t able to get the shot of these farmers. “I guess they didn’t think it looked too appetizing.”

The Solution: Opt for organic! The Environmental Working Group, which analyzes U.S. Department of Agriculture pesticide-residue data, has found 13 different pesticide residues on chemically grown strawberries.

2. Diet Soda

Isaac Eliaz, MD, integrative health expert and founder of The Amitabha Medical Clinic and Healing Center in Sebastopol, CA

The Problem: Dr. Eliaz stays away from any diet soda or foods, sugar-free candies, and gum containing artificial sweeteners such as sucralose, aspartame, acesulfame K, and neotame, among others. “The safety data on these sweeteners is shrouded in controversy and conflicts of interest with the manufacturers of these chemical compounds,” Dr. Eliaz warns. “Independent research strongly suggests that when metabolized in the body, these sweeteners can cause health-related issues and problems related to metabolism and weight gain, neurological diseases, joint pain, digestive problems, headaches, depression, inflammatory bowel disease, chemical toxicity, and cancer, among others.”

The Solution: If you’re craving a soda but want to avoid the shady sweeteners, fake food dyes, and preservatives found in popular brands, try a bottle of Steaz zero-calorie green tea soda or Bionade, a fermented soda that’s majorly popular in Europe.

3. Anything from McDonald’s

Joel Salatin, sustainable farmer and author of This Ain’t Normal, Folks

The Problem: McDonald’s isn’t just about food-it’s about food mentality, according to Salatin. “It represents the pinnacle of factory-farming and industrial food,” he says. “The economic model is utterly dependent on stockholders looking for dividends without regards to farm profitability or soil development.”

Fast food typically is loaded with all sorts of the ingredients mentioned earlier in our list-genetically engineered corn, food dyes, artificial sweeteners, and other bad actors in the food supply. The type of farming that supports this type of food business relies on harmful chemicals that not only threaten human health, but also soil health.

The Solution: Learn to cook! You might be surprised to find that paying extra up front for a pasture-raised chicken can be cheaper than buying prepared fast-food chicken. For instance, cooking a chicken and then boiling down the bones for a rich, disease-fighting stock can yield up to three meals for a family! (Here’s how to make homemade stock.) Find sustainable farmers at LocalHarvest.org.

4. Canned Tomatoes

Frederick vom Saal, PhD, professor of biological sciences at the University of Missouri

The Problem: The resin linings of tin cans contain bisphenol-A, or BPA, a synthetic estrogen that has been linked to ailments ranging from reproductive problems to heart disease, diabetes, and obesity. Studies show that the BPA in most people’s bodies exceeds the amount that suppresses sperm production or causes chromosomal damage to the eggs of animals. “You can get 50 micrograms of BPA per liter out of a tomato can, and that’s a level that is going to impact people, particularly the young,” says vom Saal. “I won’t go near canned tomatoes.”

The Solution: Choose tomatoes in glass bottles (which do not need resin linings), such as the brands Eden Organic and Bionaturae. You can also get several types in Tetra Pak boxes, such as Trader Joe’s and Pomi.

5. Bread

William Davis, MD, cardiologist and author of the New York Times best-seller Wheat Belly

The Problem: Modern wheat is nothing like the grain your mother or grandmother consumed. Today, wheat barely resembles its original form, thanks to extensive genetic manipulations of the 1960s and ’70s to increase yields. “You cannot change the basic characteristics of a plant without changing its genetics, biochemistry, and its effects on humans who consume it,” Dr. Davis notes.

In his book, Dr. Davis makes the case that modern-day wheat is triggering all sorts of health problems, everything from digestive diseases like celiac and inflammatory bowel disease to acid reflux, obesity, asthma, and skin disorders. “If there is a food that yields extravagant, extraordinary, and unexpected benefits when avoided, it is bread,” says Dr. Davis. “And I don’t mean white bread; I mean all bread: white, whole wheat, whole grain, sprouted, organic, French, Italian, fresh, day-old