Whether it’s hidden ingredients or compounds that may be damaging your digestive system and metabolism, these five foods should be quickly and permanently banished from your pantry and refrigerator:

1. Packaged Instant Oatmeal

While it’s true that oatmeal can be one of the healthiest foods in your kitchen, loaded with heart- and waist-friendly fiber, packaged oatmeal is a different story. This quick alternative is often packed with added sugar. Added sugar first thing in the morning is just asking for a mid-morning energy crash, not to mention the extra calories. Instead of starting your day with a blood-sugar spike from a bowl of instant oatmeal, opt for plain rolled or steel-cut oats flavored with nuts, fresh chopped fruit and your favorite milk. If a quick and easy breakfast is your goal, cook a large batch of oats ahead of time or try recipes like this for overnight oats.

2. Margarine

If you choose sticks of margarine because you think it is a healthier option than regular butter, you may be getting more trans fat in your diet than you’d like. Trans fat has been shown to negatively impact blood cholesterol levels and overall heart health. In the interest of public health and personal image, many manufacturers are looking for ways to remove trans fat from products such as packaged foods and bakery items. To still get the buttery flavor while limiting trans fats (and avoiding the saturated fat in regular butter), replace the sticks with soft margarine in a tub. Better yet, gradually ease margarine and butter out of your kitchen and your diet to save on calories and fat.

3. “Reduced Fat” Packaged Foods

With fewer grams of fat and something of a health halo, these foods often seem like the smart choice at the grocery store. Unfortunately, when fat is removed, manufacturers often replace it with extra sugar to maintain flavor. Just like the packaged instant oatmeal, this added sugar can lead to extra calories and an energy crash down the line. Instead, stick with the regular version of these foods and enjoy occasional smaller portions to get the taste without undoing all your hard work in the gym.

4. “Diet” soda

Over the last several years, more and more research has examined the effects of artificial sweeteners in soda and other foods. Essentially, the results suggest that you may be better off skipping artificially sweetened foods and drinks entirely. Some studies show they may actually trigger the appetite to kick in—the opposite of what you probably want—and another recent study indicates that artificially sweetened diet soda may actually alter the healthy bacteria in your stomach, which could affect how your body digests food and possibly lead to glucose intolerance. No thank you!

5. Microwave Popcorn

Popcorn itself can be an incredibly healthy snack. As a whole grain, it contains a significant amount of fiber and recent research suggests it actually contains high levels of antioxidants. The key is sticking to air-popped popcorn because microwave popcorn is often loaded with calories, fat and sodium (plus, there are some indications that the bag and flavoring may pose a health risk). Ditch the microwave popcorn and save money and calories while you amp up nutrition with popcorn recipes like this.

What foods do you avoid keeping in your kitchen and why?

With a world of conflicting diet recommendations and research results, it’s important to rely on dietitians to provide the most accurate information and sound advice tailored to individual needs. A strong nutrition program is a must for a successful fitness program.