A new study suggests that cutting out a single category of foods could nearly double people's weight-loss results.The study, published in the journal Nature Medicine on Aug. 4, found that overweight adults who ditched ultra-processed foods (UPFs) lost nearly twice as much weight over a two-month span as those who did not.UPFs include microwave meals, sodas, potato chips and packaged cookies, among others.5 EVERYDAY FOODS AND DRINKS SILENTLY DAMAGING YOUR LONG-TERM HEALTH, SAY NUTRITION EXPERTSBut they can also include items marketed as "health foods," some medical professionals say.UPFs go through multiple processes to be "stabilized for consumption," Dr. Jeffrey Kraft, a bariatric surgeon at Hackensack Meridian Palisades Medical Center in New Jersey, told Fox News Digital."Processed foods are not natural foods," he said. "They've gone through a factory or been chemically changed so they last longer on the shelf."Kraft said they "don't trigger our normal satiety, which is feeling full."MEDICAL EXPERTS WARN 'BIG FOOD' IS FIGHTING BACK AGAINST OZEMPIC WITH ADDICTIVE ITEMS FOR SALE"They are almost always combined with other unhealthy things, like high fructose corn syrup, emulsifiers and hydrogenated oils."Weight loss with whole foods often comes down to their higher fiber and protein content, which helps people feel fuller longer, said Ashlee Carnahan, a registered dietitian nutritionist at Henry Ford Health in Detroit.Even protein bars can be considered ultra-processed but Carnahan said eating them occasionally is OK."Keep in mind, a boiled egg provides 7 grams of protein and is the most complete whole protein-based food," she told Fox News Digital. "I always encourage whole food first."For those who don't think they have time to prepare meals, try focusing on foods "in their whole state," said Carnahan.These include apples, bananas, carrot sticks, nuts and seeds, natural peanut butter and plain Greek yogurt."These are all great foods that just take a little planning and are easy to consume with little preparation," she advised."Slowly increasing your fruit and vegetable intake to 3 cups of vegetables and 2 cups of fruit per day is a good place to start and supports an overall healthy diet."CLICK HERE TO SIGN UP FOR OUR LIFESTYLE NEWSLETTERAbove all, Carnahan said consumers need to pay close attention to what they're putting into their bodies."When consuming processed foods, I would encourage everyone to read the label most importantly, looking at total grams of sugar and sodium," she said. "The lower, the better."For more Lifestyle articles, visit foxnews.com/lifestyleA quick tip Kraft suggested is to "shop the perimeter" of the grocery store."That's typically your healthiest foods, with a couple of exceptions," he said. "Things that are going to expire relatively quickly are better for you, just generally speaking."Kraft said he usually tells his weight-loss surgery patients to replace breakfast with a low-calorie protein shake."The ultimate thing when it comes to weight loss is you have to sleep," he added."If you're not sleeping well meaning you have sleep apnea that's undiagnosed you're never going to lose weight."