Why You Should Think Twice Before Trying The CICO Diet

A medium-sized donut is 198 calories, nearly the same number of calories in a skinless chicken breast, per the United States Department of Agriculture. Yet, we may feel guilty after a Dunkin' run, but pat ourselves on the back for lunching on a lean, grilled fillet. If weight loss is all about "calories in, calories out," or CICO as a popular Reddit forum has abbreviated it, then as long as we stay within a specific calorie limit every day, theoretically, those calories should be enjoyed on whatever foods we like the most, proponents of the CICO diet claim, making donuts fair game. Except, many nutrition experts argue that weight loss is not as simple as eating fewer calories than you burn.

According to Cynthia Sass, MPH, RD, our bodies simply don't process all calories in the exact same way. "We now know that the quality of the calories you consume — as well as the macronutrient balance and timing — all impact metabolism, satiety, and how your body utilizes calories," Sass told Health. "It's not as simple as a math equation."

Protein-rich foods — like grilled chicken — as well as foods that contain healthy fats and fiber, are more filling than highly processed foods containing refined sugar — aka, that donut. Plus, your body exerts more effort burning protein than simple sugars (per Healthline). This doesn't mean you can't lose weight eating high-sugar foods if you stay at a calorie deficit, but according to experts, it will be a longer, harder journey than if you chose nutrient-rich options. "We don't burn calories the same way every day. For example, we burn calories from carbs more quickly than those from fat or protein. That's why when you eat fat or protein, you'll feel more satisfied," Bonnie Taub-Dix, RDN, told Prevention. Erin Palinski-Wade, RD, CDE, LDN, CPT, agreed, and gave an example: "For instance, following a 1,500-calorie diet packed with simple sugars will not only leave you hungry, but you'd see slower results as your body doesn't have to work very hard at all to digest sugar."

But what if you really, really love donuts? You can still have them! Just be mindful of portion sizes and make them an occasional treat — rather than a dietary staple. "Ultimately, you want to find a diet that's sustainable, flexible, and enjoyable," said Torey Armul, a registered dietitian (via Vice).