A study published Tuesday in JAMA followed 609 overweight adults for a year and found that counting calories and watching portion sizes to lose weight were ineffective for weight loss. Instead, people who slashed sugar, refined grains, and highly processed foods in favor of whole foods like fruits and vegetables lost more weight than those who calculated every meal's calories. What's more, researchers found that trying to personalize diets to genetics or how their individual insulin responded to carbohydrates was ineffective, leading the team to question a spate of recent studies that suggest some people are more able to lose weight than others simply because they're genetically able to do so. The study goes against the advice that health agencies like the Center for Disease Control and Prevention have long stood by keeping food diaries and meticulously tracking each food's caloric output. In short: Eat your fruits and vegetables, and a lot of them.