Prepackaged 100-calorie snack packs. “Lean” frozen dinners. Diet soda. If you are trying to eat well and lose weight, there are many options at the grocery store that seem like healthy choices. However a new study published in the journal Cell Metabolism found that participants who ate a diet comprised of highly processed foods gained more weight than their study counterparts eating an unprocessed diet, even when matched for calories, fat, sugar, fiber and other vitamins and minerals.
The small study, which took place over four weeks, provided meals that contained similar nutrients to participants in the ultra-processed and the unprocessed groups. Participants in the ultra-processed group ate more and consumed more calories during the meals and gained an average of 1% of their body weight after two weeks. The unprocessed group lost 1% of their body weight in the same amount of time.
Processed Foods Common in U.S. Diets
While study participants were assigned to either an ultra-processed or unprocessed group, the average person usually eats a mixture of both every day.
A separate study published in BMJ Open found that in the U.S., an average of 58% of daily calories come from ultra-processed foods. The most common choices were: bread; soft drinks, fruit drinks and milk-based drinks; cakes, cookies and pies; salty snacks; frozen and shelf-stable plates; pizza and breakfast cereals.
“Ultra-processed foods typically have a long shelf life and cook quickly or can be eaten on the go,” said Bonnie Buckingham, a registered dietitian with Samaritan Weight Management Institute. “They are very convenient and are often fortified with nutrients but can’t replace whole foods for health and weight management.”
Identifying Ultra-Processed Foods
There is no universal definition of an ultra-processed food, but in general it is made of primarily an inexpensive commodity — like corn, soy or wheat — with added fat, sugar or salt. An ultra-processed food usually depends on additives for flavor rather than culinary ingredients used in home cooking, and has chemical preservatives to keep it from getting stale or moldy.
Buckingham notes that many ultra-processed foods have misleading advertising on the front promoting “good source of vitamins,” “natural flavors,” “non-fat” or other healthy-sounding claims. To find out what’s really in the package, you’ll need to read the ingredients on the back of the label. If you don’t recognize an ingredient as something you might cook with at home (Disodium guanylate? Potassium sorbate?), it’s likely best to avoid the product.
“If you are working on losing weight, a processed meal or snack is not the best choice, even if it is low in fat, sugar or calories,” said Buckingham.
Processed Foods & Weight Gain
Why do people gain weight on processed diets? Buckingham notes it is likely a combination of factors.
Processed food is created to taste good and feel good in your mouth so that you want to eat more. However, consider that during processing most of the fiber is removed from the raw ingredients. Low fiber content means you can eat more before feeling full and calories become more concentrated.
“Food needs fiber so that you feel satisfied when you eat it,” said Buckingham. “It also balances blood sugar so you don’t get highs and lows, and keeps you feeling full longer.”
The combination of easy to eat, and easy to eat too much can lead to consuming excess calories and inevitable weight gain.
How To Cut Back
In many cases, buying foods that are less processed means you will have to do a little more work. As you examine your diet, make changes slowly so they are more likely to stick.
Try these tips for eating less processed food:
1. Plan Your Week
Buckingham notes that many people she counsels don’t have a plan for dinner each night. That makes it more likely you’ll be shopping for groceries at the end of the day when you’re tired and hungry, or might settle on another frozen dinner because the fridge is empty. Instead, make a menu and shop for supplies at the beginning of the week. Your menu should include a selection of foods that you are used to eating while you introduce less processed meals.
2. Buy Bread With a Short Expiration Date
Bread is the most common ultra-processed food people eat, so choosing a less processed version can make a big difference in your diet. Look for a whole grain variety with a short expiration date, usually about a week from time of purchase. Refrigeration can dry out bread, so keep it in the freezer if you don’t go through a loaf before it spoils.
3. Use Homemade Versions of Meal Helpers
Instant potatoes, quick cooking rice, salad dressing, seasoning packets and more can all be replaced with homemade versions. Many salad dressing recipes are simple, requiring just oil, vinegar and herbs. If there is a seasoning packet you like, look at the ingredients for the spices it uses and then make your own next time to cut down on sodium and preservatives.
4. Make Your Own Freezer Meals
When you make them yourself, frozen meals are a great way to get a healthy dinner on the table in a hurry. From soup to casserole to tacos, the internet and Pinterest are full of recipes for batch cooking at home. Just search for “healthy freezer meals.”
5. Add a Vegetable & Fruit to Each Meal
Half of your plate at each meal should be fruits and vegetables, says Buckingham. A side salad or grilled Brussels sprouts will help fill you up, or choose frozen veggies if that’s easier to keep on hand. Fresh fruit is a good alternative to dessert.
6. Replace Savory Snacks
Instead of snacking on chips and crackers, choose unsalted nuts or air-popped popcorn. Avoid artificially flavored nuts or popcorn as these can have chemical additives and high sodium.
7. Build Your Own Flavor
Whether you like strawberry yogurt or Parmesan boxed pasta, that flavor usually comes from chemical additives, sweeteners and sodium. Buy plain versions and add your own fresh ingredients for flavor when possible.
8. Be Wary of Modified Foods
Foods that are labeled sugar-free or fat-free have often been modified with chemical additives so they retain a good mouth feel and familiar flavor. Avoid these when possible.
9. Bake Up a Sweet Treat
If you feel like cookies or a cake, pull out grandma’s recipe and make it yourself from scratch — no mixes or canned frosting allowed. Your homemade confection won’t have the additives and preservatives of the store-bought version, and unless you’re an avid baker the mess and hassle will likely limit how often you indulge.
10. Buy the Tools You Need
Invest in a rice cooker, Instant Pot or Crockpot if you don’t have much time in the evening to cook. When ingredients are added in the morning, these can be programmed to have dinner ready when you get home. This can be especially handy for longer-cooking whole grains, beans or meat.
11. Drink Water
Soda, diet soda, juice, flavored teas or coffees and energy drinks are empty calories with chemical additives and little nutritional value. Drink water or sparkling water instead. Unique combinations of fruit and herbs can add flavor.
“Don’t drive yourself crazy trying to eliminate every processed food,” said Buckingham. “Instead, think about making small changes to add in nutritious, whole foods to your diet.”Learn more about whole foods and healthy treats or watch our video recipes for more