The Truth About “Calories In, Calories Out”

March 9, 2021


Culina Health

We’ve all heard the age old mantra, “calories in, calories out,” right?

This post is for the skeptic – the person who prides themselves on obtaining their information from verified sources and not from click-bait headlines or social media influencers. It’s for the person who knows that a healthy lifestyle is a balance between proper nutrition and physical activity. This post is for those who are doing everything right, making informed choices, and still struggling.

Unfortunately, there are no quick fixes when it comes to healthy weight loss. You may feel secure thinking that weight loss is just a simple equation: burn more calories than you consume. You’ve bought the fancy fitness tracker, the food scale, and downloaded My Fitness Pal. You’ve told yourself “this time will be different,” only to be disappointed. After a bit of initial weight loss, your progress stagnates. You know that “calories in, calories out” (CICO) works because well – it’s science! You double-down on your restrictions, only to see zero results. You still feel stuck.

You are not alone. So many of our clients here at Culina Health have been there. We have access to unlimited information and advanced tools to help us reach our health and wellness goals. So why haven’t more people succeeded?

What most accessible sources fail to mention is that weight loss is a bit more nuanced than CICO. While I could write a book about all the factors that go into reaching and maintaining a healthy weight for your body, I want to spend a little time focusing on what happens to our musculoskeletal system when we subject our bodies to periods of restriction. The outcome may be what is preventing so many people from reaching their health and wellness goals.


The consequences of undernutrition

            Let’s talk about basal metabolic rate (BMR). This is the amount of energy your body requires to perform its normal healthy functions at rest. This number does not take into account energy needed for any form of physical activity or energy needed to digest food. If you are an avid calorie counter, you likely know your BMR.

Now, how many times have you tried to eat exactly that many calories or even slightly under? Or maybe you ate a little more and then exercised enough to bring your net intake for the day below this number. Well, you’ll likely lose some weight, but your body still has a requirement for energy and protein in order to survive.

In a perfect world, this energy we need would come from our fat stores. Unfortunately our fat stores don’t include protein, which is required for enzyme creation and tissue repair. That protein is going to come from your muscle tissue. Here’s the bad news: less muscle tissue → lower BMR → less energy required by the body → easier to regain weight in the future.

Several studies support the principle of “metabolic adaptation,” a series of shifts that take place in the body when exposed to long-term caloric deficits. In addition to a decrease in muscle mass, hormonal shifts influencing hunger and satiety take place. This is your body’s way of encouraging you to increase your calorie intake to meet the body’s baseline needs. This means that as you continue to maintain strict calorie deficits, you may become more fatigued, experience diminished weight loss results, and feel hungrier. Unfortunately, raising your BMR back to its original rate is challenging, even if you gain back the weight you originally managed to drop.


Balance is key

            So how does anyone manage to maintain a healthy body during a period of weight loss? It really boils down three guidelines.

01 – Slow and steady wins the race.

Accept that a slow, steady weight loss is better suited for long term success. A caloric deficit of 250-500 calories is best.  Eating below your BMR is detrimental to your muscle and bone tissue and will only hurt you in the long run.

02 – Moderate amounts of resistance training will achieve more than hours of cardio.

Getting the right amount of physical activity can help speed up weight loss and slow down muscle and bone loss, provided that you’re still eating enough to meet your body’s energy needs. While you may feel the desire to sweat it out with hours upon hours of cardio, consistent resistance training is the gold standard when it comes to building and retaining muscle.

03 – Quality is just as important as quantity.

The quality of your diet is just as important as the number of calories it contains. Choose nutrient-dense foods such as fresh fruits and vegetables, whole grains (yes, carbs too), and lean proteins. Try to limit highly processed foods, added sugar, and refined carbohydrates, as they do not contain the same micronutrients as whole foods.


Interested in more science-backed nutrition tips from registered dietitians? Follow us on Instagram at @culinahealth for more!


Any general advice posted on our blog, website, or application is intended for reference and educational purposes only and is not intended to replace or substitute for any professional medical advice, diagnosis, treatment, or other professional advice. If you have specific concerns or a situation arises in which you require medical advice, you should consult with an appropriately qualified and licensed medical services provider.

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