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The great diet debate for weight loss now has a new contender on the field! The newest research shows that when it comes to weight loss, it may be how processed your food is  that really matters. When it comes to weight loss, whole foods beat out processed foods by a long shot!

New Research Sheds Light on Whole Foods and Weight Loss

The results of a recent study conducted by the NIH found that people who ate a diet high in “ultra-processed” foods gained more weight when compared to people who ate a diet based on whole foods. The “ultra-processed” foods in this study included frozen and packaged foods like white bread, juice, tater tots, crackers, chips, cookies, pastries, hot dogs and deli meat. In contrast, the whole foods diet consisted mostly of fresh cuts of meat and chicken, whole grains, beans, nuts, fruits and vegetables cooked from scratch.

What made this study interesting, is that people were actually fed the experimental diets in a controlled setting. This means they had to adhere 100% to either diet. In contrast, most nutrition studies are based on self reported dietary intake, collected through surveys or interviews.  This direct observation allowed the researchers to know for sure what each participant ate, rather than relying on people’s memories of what they ate.  That makes the results of the study even more convincing!

Weight Loss Study Design

Here’s how the study worked. Participants stayed at a research facility where they were fed either the “ultra-processed” diet or the “whole foods” diet for 2 weeks each. Both diets were designed to provide similar calories, protein, fat, carbohydrate, sugar, fiber and sodium content.  However, participants were allowed to eat as much food as they wanted at each meal. To see pictures of what participants actually ate, see here.

Each day, scientists kept track of how much participants ate, energy expenditure, and other factors, like hunger, weight and hormone levels. After following each diet for 2 weeks, those on the “ultra-processed” diet gained on average almost 2 lbs, while those on the “whole foods diet” lost on average nearly 2 lbs. Granted, this study only included 20 people and lasted for 4 weeks. So more research needs to be done to explore why processed foods lead to greater caloric intake and weight gain and vice versa. However, the study had some really interesting results that could help us better understand the keys to weight loss.

Why Processed Foods Lead to Weight Gain When comparing results of both diet groups, researchers found that the “ultra processed diet” group ate on average 500 more calories per day, mostly from carbohydrates and fat. There were a few explanations for this phenomenon.  First, ultra-processed foods have a higher energy density, that is, more calories per gram of food, compared to unprocessed foods. So a smaller amount of food provides a greater amount of calories. Second, people eating the highly processed foods also tended to eat at a faster rate than the whole foods diet group. The faster you eat, the more calories you tend to consume in one meal. Lastly, the whole foods diet group had higher levels of appetite suppressing hormones and lower levels of “hunger” hormones after eating. This implies that whole foods are more filling and satisfying than processed foods.

Easy Swaps to Make from Processed to Whole Foods

We know that eating more whole foods, like fruits, vegetables, whole grains, nuts and beans can help with weight loss, but often cooking these foods can be labor intensive and time consuming. Here are 10 tips to help you quickly and easily incorporate more whole foods into your diet.

  1. Switch from white bread to 100% whole grain products, including whole wheat pasta, and whole wheat bread.
  2. Swap out white rice for brown rice, quinoa, barley, buckwheat, millet or wild rice.
  3. Skip the pastries and have plain oatmeal mixed with fruit and nuts for breakfast.
  4. Have a veggie omelet or hard boiled eggs instead of bacon or sausage.
  5. Replace flavored yogurt for plain yogurt mixed with fresh or frozen fruit.
  6. Add a side salad or cup of cooked veggies to at least 1 meal a day.
  7. Snack on nuts and fruit instead of crackers or granola bars.
  8. Snack on veggies and hummus instead of chips and dip.
  9. Make your own salad dressing out of olive oil and vinegar or lemon juice.
  10. Meal prep on your days off. Batch cook veggies, a healthy protein, like chicken or lean beef and a whole grain or potatoes. Separate into individual servings and eat for lunch or dinner for up to 3 days.

Processed foods are convenient, fast and cheap, but ultimately aren’t as satisfying or nutritious as whole foods. Making time to eat healthier foods is worth it in the long run. For more tips on healthy eating for weight loss, check out this article. Want more comprehensive advice on how to lose weight? Schedule an appointment with our Registered Dietitian Nutritionist, Joanna Eaton, by calling 301-288-1319. Now accepting most health insurances and offering telehealth visits!