Busting the Myth: Calories In – Calories Out = Body Fat

“We do not get fat because we overeat, we overeat because we get fat” –Gary Taubes

 As a practicing dietician/nutritionist for over 30 years, the one question that customers and clients have asked me the most is, “Do you have something that can help me lose weight?” Since the early 1990’s my response has been relatively consistent; supplement formulations and prescription medications for weight control are limited in their effectiveness, they will NOT produce a rapid or lasting reduction in body fat.  I would counsel people that Losing weight requires a complete lifestyle change which includes adopting a carbohydrate-controlled diet that removes refined, grain-based carbohydrates and all sources of added sugar.  In hindsight, I realize that my recommendations were consistent with fundamental nutrition science models of obesity with the exception of the calories in, calories out paradigm that has been established in medical practice since the 1960s.  It’s always been my opinion that body fat accumulation results primarily from overconsumption of lipogenic foods like refined carbohydrates and sugars and not excess calorie consumption.

If our current state of affairs is any indication, Americans’ are definitely tipping the scales.  Nearly three-quarters of American men and more than 60% of women are obese or overweight.  As for young boys and girls under the age of 20, 30% are either obese or overweight.  How did this happen? Why is everyone getting fatter? It’s important to understand that this situation did not occur overnight.  Obesity is a time-dependent condition, it develops slowly over decades.  You may be a little overweight as a child or young adult, and as the years progress, you average 1 to 2 pounds of weight gain per year.  It doesn’t sound like a lot but over 40-50 years it’s not uncommon to be carrying 80 lbs. of excess body fat.  Literally speaking, thousands of books, articles, programs, facilities, and products have been created to explain why we get fat, and each approach claims to have the “correct” explanation and solution independent of any other contributing factors. So what causes weight gain? Is it calories, refined carbs, and sugar, wheat, fat, animal protein, snacking, lack of sleep, poverty, digestive function, genetics, stress, dairy products, or food addiction?  Every self-styled expert has an opinion and book to sell.  Allow me to propose an idea:  maybe weight gain cannot be limited to one cause or behavior, but rather is multi-factorial.  Every disease or disorder in the body results from many biological, chemical, and environmental factors converging to produce a disordered state.  Why would weight gain be any different?

If we’re going to understand how we get fat, it’s extremely important to differentiate between the proximate and ultimate causes of disease.  The proximate cause of gaining weight could certainly be associated with calorie consumption, age, stress, sleeping problems, gut issues, and lack of discipline, but these do not explain, ultimately, why we’re getting increasingly fatter year after year.  Fifty years of obesity research and the obsessive adherence to the calorie-based theories of obesity have completely failed to explain why we get fat and how to fix it.  Since the 1950’s our “authorities” in government and medicine have told the American people to reduce consumption of dietary fat from animals and increase consumption of bread, pasta, and potatoes, which gave us the dreaded food pyramid-a counterfactual guide to getting fat.  Doctors and dieticians told us to eat fewer calories and exercise more, and if that didn’t work we were “fat-shamed” and told that you’re lazy or undisciplined, a product of sloth and gluttony.  So where did these recommendations take us?  From 1976 to 1996, our average fat intake decreased from 45% of calories to 35% of calories.  Butter consumption, in particular, decreased 38% while animal protein consumption decreased 13% and egg consumption decreased 18%.  At the same time, consumption of grain-based carbohydrates and sugars increased by over 30%!  This adoption of the low-fat diet, which ultimately became the Dietary Goals for the United States was completely untested at the time, no one knew what effect it would have on human health.  Today, it is estimated that refined carbohydrates and sugars comprise 65-70% of the typical American diet.  What result did this have on the health of Americans?  The incidence of heart disease did not decrease as expected, in fact, the research efforts to prove that saturated fat from animals caused heart disease have since been completely disproven!  And what about restricting calories while increasing exercise (eat less, move more) as a means to lose weight.  Rates of obesity have dramatically increased from 14% in 1960 to 40% in 2010.  Obviously, the current paradigm is a complete failure-reducing calories and exercising more does not work.

Another nail in the coffin for the calorie-reduction theory of obesity is the fact that obesity runs in families.  Obese children often have obese siblings and parents, and typically have a 200-400% increased risk of becoming obese as an adult. Studies conducted on adoptive families show that 70% of your tendency to gain weight is under genetic control.  If obesity is simply a product of calorie imbalance, then how do you explain the overwhelming genetic influence? Here, it’s important to acknowledge that just because obesity is largely genetically determined, it doesn’t mean that you should give up, just the contrary, 30% of your tendency to gain weight is under YOUR control!  When you understand that the body’s fat mass is hormonally controlled you can take dietary and lifestyle measures that will allow you to achieve lasting weight loss.  Never allow a genetic predisposition to determine your health and happiness!

Exercise, the second half of the equation in the eat less, move more approach is a false hope for anyone looking to lose a significant amount of body fat.  In every community, there are multiple fitness centers, gyms, personal training centers, or online fitness programs, not to mention the thousands of people who own in-home treadmills, spin bikes, and barbells.  By now, you would think that we would all be thin and in excellent shape.  The reality is that we’re just getting fatter.  Exercise as a means to burn stored body fat is a myth!  As a percentage, exercise will only contribute 5% to your weight loss efforts.  Why is this so?  The human body is under constant homeostatic control, which means that our physiology is always trying to maintain a stable, normal, balanced state of functioning.  When you decrease calories in and increase calories out through exercise your body will respond by activating hormones that stimulate appetite, making you eat more.  Your body is always trying to maintain a constant weight as determined by your hypothalamic set point (the body’s internal thermostat).  Also, in response to an increase in calories out, your body will decrease its basal metabolic rate to compensate for the imbalance in calorie usage.  Your metabolism will actually slow down to compensate for the increase in energy expenditure through exercise. Decreased caloric intake can decrease basal metabolic rate by up to 40%.  Conversely, increasing caloric intake can increase basal metabolic rate by 50%.  The moral of the story is that in the short term you can trick your body into losing weight by decreasing calories in and increasing calories out with exercise, but over time compensatory mechanisms will take over, and your appetite with increase while your basal metabolic rate decreases to bring you back to your set point for weight.  But let’s not throw the baby out with the bathwater.  It’s my opinion that exercise, as part of a healthy lifestyle, can help you build muscle and increase aerobic endurance, both of which will assist in the weight loss process, but it should never be relied on solely as a means to burn stored body fat.  Your body is smart, it wants to defend the current level of fatness (setpoint) and will adjust metabolic function and appetite to achieve its goal.  Don’t abandon exercising or hesitate starting to exercise based on its anemic contribution to weight loss; I could write a book on the health benefits of exercise, and many have already.  If you want to live the healthiest, longest life possible, exercise is the closest thing we have to a “fountain of youth”.  Exercise can support your weight loss efforts if your focus is not calorie reduction, but control of the TYPES of calories you’re ingesting and WHEN you’re eating them.

All diets succeed and all diets fail.  Anyone can lose weight on almost any diet for a short period of time, but in 6-12 months any weight that was lost will be regained.  Sound familiar? Any diet that follows the calories in-calories out = body fat equation will end in failure.  This has been scientifically proven.  Have you tried any of these popular diets: low-fat, Zone diet, Dean Ornish diet, South Beach, Whole 30, Weight Watchers, Nutri-System, Medi-Fast, Isogenics? None of them will produce lasting weight loss.  Any diet that results in permanent weight loss is actually not a diet at all, it’s a lifestyle modification that targets the TYPE of calories consumed and WHEN they’re consumed, not the amount.  In my experience, the most effective way to lose weight through diet is with a carbohydrate-controlled lifestyle that removes all added sugars, refined, grain-based carbohydrates, and sweetened beverages.  Dietary plans like the ketogenic diet, paleo diet, and any carbohydrate-controlled pescatarian or vegetarian diet have been found to produce lasting weight loss as long as calories aren’t restricted. So how can 50 years of medically sanctioned dietary advice be as useful as an airplane with one wing?  The evidence is conclusive, the calories in-calories out = body fat equation is based on four false assumptions:

1)  Calories in and calories out are not dependent on each other, rather they are independent variables.  If you decrease your calorie intake by 30% this will trigger a decrease in calorie expenditure by 30%.  You may lose some weight in the short term (1-6 months), but your body will regain the weight to maintain homeostatic balance.  Here’s an example.  Let’s say you weigh 250 lbs. and decide to go on a calorie-controlled diet.  In a few months you experience a 50 lb. weight loss and now weigh 200 lbs.  Keep in mind that your body set weight (internal thermostat) is 250 lbs., and if you do nothing to influence the setpoint your body will work against your wishes to regain the 50 lbs. that you recently lost.  It accomplishes this by increasing ghrelin, a hormone that increases appetite, while simultaneously decreasing satiety hormones like amylin, peptide YY, and cholecystokinin.  At the same time, your body will decrease its total energy expenditure by lowering basal metabolic rate, body temperature, heart rate, blood pressure and heart volume, all in a desperate attempt to conserve energy and get you back to 250 lbs.

2)  Basal metabolic rate is stable.  People think that exercise = calories out.  Actually, total energy expenditure = calories out, and exercise is just a small part of the equation.  Total energy expenditure is the sum of basal metabolic rate, thermogenic effect of food, non-exercise activity thermogenesis, post-exercise oxygen consumption, and exercise.  The only one that is under your control is exercise, and your total energy expenditure (calories out) can fluctuate 50% depending on calorie intake.

3)  Consuming calories is a conscious decision and fat stores are unregulated.  Is eating really a deliberate act?  Overlapping hormonal mechanisms in the central nervous system and digestive system directly influence what you eat, when you eat, and how much you eat. Remember, every biochemical system in our body including all organ systems is under homeostatic control.  Your height is regulated by hormones, blood sugar is controlled by insulin and glucagon, sexual maturation is controlled by estrogen and testosterone, and body temperature is controlled by thyroid hormones.    It shouldn’t surprise you that Calories in and calories out are controlled by hormonal signals.  The growth and maintenance of fat cells depend upon multiple hormonal pathways including insulin, leptin, adiponectin, hormone-sensitive lipase, lipoprotein lipase, and adipose triglyceride lipase. Obesity is a hormonal disorder, and until you address the underlying hormonal dysregulation lasting weight loss will not be achieved.

4)  A calorie is a Calorie.  Is a cat a cat? Is a car a car? No.  Do all calories cause weight gain? No, they don’t.  A tablespoon of coconut oil or olive oil will have a completely different metabolic response than a tablespoon of sugar.  Eating a piece of bread or a baked potato will increase blood sugar and provoke an insulin response from the pancreas.  Eating a piece of steak or a floret of broccoli will have a minimal impact on blood sugar and insulin.  One calorie makes you fat, and one doesn’t. This is why carbohydrate-controlled diets like the ketogenic diet are so effective at reducing body fat; they eliminate the foods that convert to body fat.

So we know that the calorie-reduction model of obesity is flawed science.  Eating too much does not cause obesity and eating less does not cure it.  We know that lack of exercise does not cause obesity and increasing exercise does not make the fat melt away.  So what’s the solution?  If you are overweight and want to lose excess body fat you must first understand that obesity is a hormonal dysregulation of fat mass, not a result of calorie consumption. Secondly, losing weight successfully will require targeting specific hormonal pathways that influence metabolism and push the body’s thermostat (setpoint) too high. Thirdly, lasting weight loss will only be possible if you remove from your diet those foods that are converted to fat and stored in the liver and adipocyte cells throughout your body.

The dysregulation of the hormones insulin, cortisol, and leptin causes weight gain, with insulin being the primary driver of fat storage and accumulation in the body.  Insulin is the key regulator of energy metabolism and the only hormone we produce that’s primary responsibility is to store energy (fat).  Every time you eat food-protein, fat, and carbohydrates, you initiate an insulin response.  Insulin signals the body’s cells to accept glucose from the bloodstream in an effort to bring blood sugar levels back to a normal range.  Your liver takes the biggest hit; glucose is converted to glycogen and stored in the liver where it accumulates and is eventually converted to fat.  Carbohydrates and sugars will cause the largest insulin response followed by protein and fat.  The insulin response to a moderate protein, high fat diet is minimal, this is why carbohydrate-controlled diets like the ketogenic diet are so effective, they drastically lower the insulin response to food.  Getting fat is a direct result of what I call the “insulin dysregulation cycle”.  You start at a young age eating the typical western American diet that is 60-70% refined carbohydrates and sugars.  Your pancreas is constantly releasing insulin multiple times a day for weeks, months, and years.  As you get older the amount of insulin increases in response to what you’re eating, and fasting insulin levels start to rise (hyperinsulinemia).  Now you are in permanent “fat storage mode”.  The higher your insulin goes, the higher your body’s thermostat goes (hypothalamic set weight).  If your set weight is 250 lbs. your body will engage all homeostatic hormonal controls to keep you at that weight.  In obese patients, insulin levels are 20% higher and are directly correlated with waist circumference and waist/hip ratio.  The more carbohydrates and sugars you consume the more insulin you produce; the more insulin you produce the more resistant your body becomes to its effects which signal the pancreas to produce even more insulin.  The vicious cycle continues until you’ve become fat, pre-diabetic, or diabetic.  To complicate matters further, the hormone leptin, which is secreted by fat cells and travels to the brain to tell you to stop eating because you’ve eaten too much, no longer works because you’ve developed a resistance to its signal.  As the fat mass slowly increases you no longer have control over its growth cycle; insulin is converting food to fat which has overwhelmed your liver, leptin can’t control your appetite, the gut hormone ghrelin is telling you to eat, and at the same time appetite-suppressing hormones like peptide YY and cholecystokinin have stopped working.  This is all under involuntary homeostatic control because your body wants to maintain its current level of fatness.  Also working against you is the adrenal hormone cortisol.  Prolonged physical or psychological stress will elevate the fight-or-flight hormone cortisol, which causes blood sugar levels to rise and stimulates an insulin response.  This will push insulin even higher and increase the chances of developing insulin resistance, carb and sugar cravings, and weight gain.

So what is the solution?  How can you address this hormonal dysregulation and achieve a normal weight?  To me, the answer is much simpler than the question-Remove all refined carbohydrates and sugars from your diet and include a weekly program of intermittent fasting.  Yes, it’s really that simple and inexpensive. Fasting is the most effective way to lower insulin and blood sugar.  There is no supplement or medication that will work any better.  By voluntarily withholding food intake for 16, 20, 24, 36, or 48 hours you can effectively normalize blood glucose and lower insulin activity, which will help your insulin receptors to regain their sensitivity and allow your body to “feed” off its own fat stores for energy.  Fasting is humanity’s oldest healing tradition, every religion and culture in the world has benefitted from its positive metabolic effects. With the exception of pregnant/breastfeeding women, young children, and people with certain medical conditions, there is not a person on the planet that needs to eat three meals a day with snacks.  If you want to gain weight eat every three to four hours a day!  For more information on how to fast successfully please refer to my blog post: Are we ready for a paradigm shift?  What is Intermittent Fasting, and why is it helping so many people lose Excess Body Fat?  The second part of the equation is removing foods that cause a high and sustained insulin response.  It is simply NOT POSSIBLE to lose weight unless you adopt a carbohydrate-controlled diet that removes refined grains and sugars.  If you think you can lose weight by just REDUCING the number of refined carbs and sugars, your effort will ultimately fail.  I’ve seen the best results with a ketogenic style diet that is 65-75% fat, 15-25% protein, and 5-10% carbohydrate.  In my opinion, this diet is the most effective way to eat if you want to lose weight.  It will switch you from being a “sugar burner” to a “fat burner” while normalizing insulin and blood sugar levels.  We would never have survived as a species if our bodies hadn’t adapted to using fat as a fuel source.  Based on my experience, the combination of intermittent fasting with a carbohydrate-controlled diet is the winning combination for weight loss.  You can effectively address the underlying causes of weight gain-insulin resistance, high blood sugar, leptin resistance, and appetite stimulation with a simple lifestyle modification.


Michael K Chase, MS, NTP

Nutrition Science and Dietetics

Fung, J. (2016) The Obesity Code. Vancouver: Greystone Books.

DISCLAIMER: The information provided in this post is for educational purposes only, and should not be construed as personal medical advice or instruction. No action should be taken based solely on the contents of this information. Individuals should consult appropriate health professionals on any matter relating to their health and well-being. The statements made in this informational document have not been evaluated by the Food and Drug Administration. Any product discussed is not intended to diagnose, treat, cure or prevent any disease.

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