What is the CICO Diet? - How to Count Calories for Weight Loss

Another trendy diet fad people are buzzing about is the CICO (calories-in-calories-out) diet wherein you keep track of the calories you’ve consumed, and calories you’ve burned. The core premise of this diet is that you can eat whatever you want and as long as you’re able to keep your calorie intake under your calorie expenditure for the day, you can lose weight. Sounds promising right? However, this diet neglects some vital aspects of long-term weight loss and health. If you want to learn more about it, read on!

So what exactly is this CICO diet?

CICO is a weight-loss strategy that is primarily focused on caloric intake. It’s based on the idea that eating fewer calories than you burn regardless of where those calories come from can help you shed off some weight fast.

Calories In is any food or drink you have throughout the day. Calories Out are the energy your body uses for basic functions to keep you alive, like breathing and keeping your heart beating including the exercise you do on top of your basic metabolic functions.

The majority of your Calories Out is used for basic metabolic functions or just being alive. For an average person, exercise calories are only a very small portion of your Calories Out. If your CI is greater than your CO you have excess energy. Excess energy is stored in your body as fat. The goal of this diet is for the body to end up burning more calories than the amount being consumed. As a result, the body needs to burn storages of fat for the extra energy, resulting in weight loss.

While it’s true that this diet can help you lose weight, it doesn’t really take the body’s nutrient needs into account. It’s important to remember that weight in itself is not the only gauge for your body’s overall health.

How does CICO diet work?

To put it simply,

When you take in more energy than you burn, you gain weight.
When you take in less energy than you burn, you lose weight.

How many calories should you eat and burn?

Determining your calories-in number largely depends on your basal metabolic rate which is typically a guesstimate based on your gender, height, weight, the typical level of daily activity and maybe a few other factors if you’re super diligent.

On the other hand, calories-out is made up of three major elements:

Resting Metabolic Rate (RMR): the amount of energy needed to fuel the body at rest (breathing, heartbeat, blinking, etc.). This can vary from individual to individual and is mostly influenced by fat-free body mass. Age, sex, and fat mass also affect RMR.
Thermic Effect of Food (TEF): energy used to digest food (absorption and metabolism). The more food you consume, the greater the TEF. It’s usually around 10% of the total amount of food you eat.
Energy Expended through Physical Activity (EEPA): is the element that you can control the most. It also has the strongest influence on determining your calories-in number. This value is determined by the duration and energy cost of physical activities. This will differ depending on the intensity of the exercise.

The same amount of calories will have different energy costs to digest (TEF) depending on the type of food. This is greatest for proteins (20-30% energy content of the protein), followed by carbohydrates (5-10% energy content of carbs), and fats (0-3% energy content of fats).

However, the TEF is not nearly as important as your physical activity (EEPA) for calculating your total energy expenditure (TDEE). There are several online calculators that may help you determine your TDEE and EEPA (based on your activity levels).

Once you have determined what your total energy expenditure (TDEE) and physical activity (EEPA) goals are, you can set the appropriate target for daily calories consumed.

Potential Benefits of CICO

When done properly, CICO’s straightforward approach to weight loss can be highly beneficial for obese individuals who are suffering from weight-related health complications. The CICO diet is considered safe when calorie deficits are balanced with nutrient intake.

To avoid nutrient deficiencies and other potential adverse effects, consult with your doctor or nutritionist to design a healthy and balanced CICO diet that works for you

Calorie Deficits

Calorie restriction, if correctly implemented refers to reducing calorie intake by 30-40% while maintaining proper nutrition (vitamin, protein, mineral, and water intake). If done this way, calorie deficits are believed to have many health benefits including

The inverse association with tumor and breast cancer risk
Reduced oxidative stress
Lower incidence of heart disease (particularly atherosclerosis) and stroke (due largely to decreased blood pressure)
Reduced tissue injuries caused by lack of oxygen (ischemia)
Reduced cholesterol (hyperlipidemia) and obesity (through intermittent fasting)
Hormonal balance: increased insulin sensitivity (useful for diabetics) and ghrelin reduction (causes hunger)
Less inflammation
Eye protection (protects the retina and may help reduce the symptoms of cataracts and glaucoma)
Slowed aging and increased longevity
Improved brain and memory function
Slowed progression of brain diseases (e.g. Alzheimer’s Disease)

Weight Loss

Weight loss is associated with a plethora of benefits, which comprises of:

Reduced risk of heart disease and stroke (reduced blood pressure)
Lower risk of diabetes
Reduced risk of different cancers
Lower risk of asthma
Reduced risk of gallbladder disease
Improvements in osteoarthritis
Improvements in chronic back pain
Improved cholesterol levels
Improved movements
Reduced risk of stroke

Successful weight loss in the long-term can be maintained by:

Continued monitoring of your caloric intake
A support system that helps with the regulation of your health goals
Maintaining physical activity
Good mental health

Note that these benefits are limited to people who start out overweight or obese. If you are already at a healthy weight, further weight loss is not recommended. Your doctor can help you determine and reach your ideal weight.

Downsides/Potential Dangers of CICO

CICO diets may lead to health problems if improperly incorporated into your diet. Examples of these problems are:

Nutrient Deficiencies

Nutrient deficiencies can lead to a variety of problems such as:

Cancer: according to some researchers, diet contributes to about a third of preventable cancers (same amount as smoking).
DNA Damage: a deficiency in any micronutrient (folate, vitamin B12, vitamin B6, niacin, vitamin C, vitamin E, iron and zinc) damages the DNA (mimics damage via radiation).
Chronic Energy Deficiency (CED): Deficiencies in vitamin A, vitamin B, and proteins caused chronic energy deficiencies in 658 (out of 1540) drought-affected adults (observational study).
Osteoporosis: diet is important for the prevention of osteoporosis. Nutrient deficiencies (vitamin D, calcium, magnesium, silicon, vitamin K and boron) may reduce bone growth and maintenance.
Heart Disease: 509 patients with heart disease and iron deficiencies were given iron supplements over 5 to 36 weeks (meta-analysis), resulting in a 60% decrease in heart failure risk.
Birth Defects: Vitamin supplements are strongly recommended during pregnancy. Micronutrient deficiencies may lead to detrimental long-term outcomes for newborns such as survival, cognitive function, as well as increased risk of diabetes, heart disease, and stroke.
Diabetes: the body requires vitamins and nutrients (cofactors) to maintain glucose and insulin levels. Deficiencies in these nutrients may impair the glucose and insulin pathways, which may contribute to diabetes.
Obesity: Nutrient deficiencies are common in individuals with obesity, who usually eat high-calorie foods with low nutrient content. Nutrient deficiencies impact glucose and leptin breakdown, which may lead to obesity.
Hair Loss: Hair loss can be caused by deficiencies in iron, zinc, niacin (vitamin B3), fatty acids, selenium, vitamin D, vitamin A, vitamin E, folic acid, biotin, and proteins. Since hair loss can be a result of many factors, it is unclear whether nutrient supplementation will help restore hair growth.
Mental Health Problems: Vitamin B12 and folate supplements improved mood in depressed patients (RCTs), suggesting that deficiencies in these vitamins can worsen depression.
Brain Problems: Zinc deficiency has been linked to low physical activity and reduced brain activity among children. Additionally, vitamin B12 deficiency has been associated with lower cognitive functioning in adults.
Weakened Immune Response: several experiments over a period of 6 years showed that nutritional stress (protein and calorie deprivation) leads to a variety of changes in the immune response of mice, rats and guinea pigs. This may also apply to individuals deprived of nutrients.
Inflammation: supplementation with vitamin C, vitamin E, and carotenoids reduce inflammation in the body.

Inadequate and Unhealthy Calories

Some individuals who adopt the CICO diet may be doing so due to its lack of food restrictions. These people may end up eating unhealthy food while still maintaining a caloric deficit. On the other hand, other individuals may not eat enough calories. This may cause weight loss, but that doesn’t make it healthy.

Unhealthy calories (sweets, processed foods, fried foods, etc.) or an inadequate number of calories may lead to health problems like:

Inflammation: high-carb, high-sugar, and high-fat meals can be a direct cause of inflammation. Increased inflammation can make it difficult to stick to a diet by causing cravings, fatigue, psychological stress, and lack of motivation.
Stunted Growth Via Chronic Energy Deficiency: energy deficiency is associated with weight loss, reduced metabolism and reduced exercise when not enough nutrients are consumed. CED may cause stunted growth, especially in children. These individuals don’t “lose weight”, they simply grow less.
Fat Gain: Individuals with chronic energy deficiencies naturally adapt by reducing their body’s energy consumption. This means that they will not lose weight but instead will have less overall energy. Once these individuals start eating normally again (supplemented), they will experience very rapid fat gain.
Reduced Immune Response: a deficiency in total calories and proteins severely reduces the immune response. This makes individuals extremely susceptible to a variety of illnesses’ such as bacterial infections.
A Risk to Offspring: poor dietary habits will likely negatively impact the immune system response of any offspring. Unhealthy foods will lead to protein and gut bacteria changes in the body, which influence the immune system. These immune modifications may be passed down to your offspring.
Heart Disease: a poor diet is one of the most common causes of heart disease. Inappropriate eating habits (high fat, high salt, lower number of meals but larger portions) significantly increases the risk of heart disease.
Cancer: high fat, salt, and sugar diets with low fruits and vegetables strongly increase the risk of cancer (1 in 3 cancers may be diet-related).
Stress: low-calorie diets have been associated with an increase in cortisol levels. Increased stress levels lead to more unhealthy eating habits, causing weight-gain in many cases.

Difficulty Exercising

Maintaining consistent exercise during a diet can be difficult for some. But the effects of caloric deficits (fatigue, stress, lack of motivation) make it even more difficult to exercise often.

Additionally, the body of individuals with caloric deficiencies adapts by using less energy (total daily energy expenditure). Since the energy burned during rest (RMR) doesn’t vary much, individuals will have less remaining energy to use for exercise (EEPA).

A study in 12 healthy wrestlers found that short-term caloric deficits decrease exercise power (compared to a normal diet). The wrestlers had restricted calorie intake for a week.

To avoid adverse effects during weight loss, consult with your doctor to determine the best diet for you.