Does the CICO diet work?

Does the CICO diet work?

With the popularity of diets on social media, you may have heard of a newer concept called the CICO Diet. CICO is an acronym for ”calories in, calories out.” In this diet, you monitor the calories you consume from food and beverages and how many calories you burn from exercise, general daily movement and your resting metabolic rate. Then you just need to do some simple math:

  • To lose weight, consume fewer calories than you burn
  • To gain weight, consume more calories than you burn
  • To maintain weight, consume the same amount of calories that you burn

But did you know that just about every diet uses the CICO principle? Many diets will claim that cutting sugar, carbs, fat, animal foods or whatever is hot at the moment will magically melt away fat. Often, these diets can help because eliminating certain categories naturally decreases the ‘calories in’ half of the equation, whether you realize it or not.

Research studies have shown that it’s really that reduction in total calories that produces weight loss and, more importantly, reduces body fat, especially long-term. Some diets like low-carb and keto can lead to a larger weight loss in the beginning, but most of the weight lost is water, not fat, due to glycogen stores releasing large amounts of water. Not all weight loss is the same — losing water weight doesn’t have the long-term health benefits of reducing body fat.

Anyone looking to lose weight or maintain their weight can benefit from the CICO Diet. The diet is designed to promote weight loss by monitoring your calorie intake and keeping calories in a range that’s sensible for you.  However, if you have an eating disorder, you should not try the CICO diet. The heavy reliance on counting calories won’t help you develop a healthy relationship with food and can be triggering. Other approaches like increasing the amount of vegetables and fruit in your diet are a better fit if you’re experiencing an eating disorder.

Like any eating plan, there are pros and cons to the CICO Diet:


  1. Don’t like feeling deprived or restricted? Technically, there are no “forbidden” foods on the CICO Diet. You can eat what you like as long as you stay within your calorie budget since all calories are considered “equal.”
  2. You can combine the CICO principle with any eating plan such as Mediterranean, DASH Eating Plan, vegetarian, vegan, reduced-carb or others.
  3. Many free websites and apps are available for monitoring calories. Seeing the number of calories can be an eye-opener for many people and help identify easy ways to improve.


  1. You need to know your individual calorie needs for any of this to make sense. Estimation equations get you in the ballpark but aren’t accurate for everyone, and it’s very important to not go too low in calories either. See a registered dietitian for guidance in finding the amount right for you.
  2. Let’s face it, tracking calories isn’t fun and can be challenging to keep up long-term.  It requires consistency, being skillful with portion sizes and recording as well as being honest about what and how much you’re eating.
  3. Quality of calories matters! Reducing calories shouldn’t stop you from getting enough quality food. Our insides can suffer if more highly processed foods are consumed instead healthy food, and not enough nutritious food can lead to nutrition insufficiencies, deficiencies and eventually health problems. “Junk” food will make you feel like junk.

The CICO Diet can be effective in losing weight and body fat, but it does require work such as tracking what you and drink consistently. The best option is to combine CICO with eating mostly nutritious foods. Your calorie needs can be tricky to calculate so consider seeing a registered dietitian for help creating a well-balanced plan to meet your individual calorie and nutrient needs.

Now is the perfect time to make an appointment with a primary care physician. Whether you live in Illinois or Wisconsin, it’s easy to find a doctor near you. 

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About the Author

Heather Klug
Heather Klug

Heather Klug, MEd RD is a registered dietitian and cardiac educator at the Karen Yontz Women's Cardiac Awareness Center inside Aurora St. Luke's Medical Center in Milwaukee, WI.