What Causes Weight Gain (the truth)

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By: Alirio Zavarce

Causes of Weight Gain

Want to know what’s causing you to gain weight? Understanding the reason why your body stores fat is key in losing weight.

Counting calories only works in the short term and is not the real reason why obesity has become an epidemic. When you look into hormonal imbalances, you find answers.

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Have you ever noticed how people you know gain weight slowly throughout time?

Pretty common, isn’t it?

In this article, you will learn why people gain weight?

You will be amazed of what you have and haven’t been told!

Are you ready?

Let’s dive right in.

Weight Gain as a Caloric Imbalance

Weight Gain as a Caloric Imbalance

If you eat too many calories, you will get fat. That’s what they tell you.

When you go to the store, everything, or almost everything, is fat free.

In spite of all the effort to keep people away from high-fat food, obesity rates remain high year after year.

Just look around. Almost everybody is overweight!

For many years, weight gain has been attributed to a personal choice problem, a behavioral issue. You either eat too much or exercise too little.

Conventional weight loss treatments target obesity as an imbalance between the amount of food you eat and how much exercise you undertake.

Too many calories coming in vs too little coming out.

If you eat too much, you’re a glutton…

…and if you don’t exercise enough, you’re lazy.

You made that choice yourself since you’re in control of your own actions; therefore, being obese is a synonym of a phycological problem characterized by low willpower. Supposedly!


What if what you’ve been told simply doesn’t work?

I don’t mean to bore you, but to make a point, I think it’s important we look at a few studies quickly.

Studies on Cutting Down Calories

In 1917, Arthur Harris and Francis Benedict, in their study A Biometric Study of Human Basal Metabolism, put 12 young men on a semi-starvation diet of 1400-2100 calories per day.

Guess what? The subjects lost weight, BUT they constantly complained of being hungry and cold.

They measured their basal metabolic rate, which is the level at which the body uses energy while at rest to keep vital functions going, such as breathing and keeping warm.

This is a very important concept, so I’m going to repeat it.

The basal metabolic rate is the level at which the body uses energy while at rest to keep vital functions going, such as breathing and keeping warm.

And what they found was that patients’ metabolism decreased by 30%! They measured a reduction in blood pressure, heart rate, ability to concentrate, and strength during physical activity.

This 30% decrease in metabolic rate explains why they were cold: their bodies were shutting down by turning down heat production as a way of reducing caloric or energy expenditure.

In another study in 1944 by Ancel Keys titled The Biology of Human Starvation, they put 36 men on a 24-week semi-starvation diet that consisted of 1570 calories per day.

What they found was that the subjects’ resting metabolic rate declined by 40%!

Their heart volume shrank by 20%; heart rate slowed down; and their body temperatures dropped. There were also psychological effects such as obsessive thoughts about food and binge eating.

In 1995, another study found that as the subjects gained weight, their bodies’ metabolism increased to burn those calories.

And on the contrary…

…when their bodies lost weight, their bodies started to shut down.

So, it seemed that their bodies had mechanisms of compensation to return to their INITIAL WEIGHT!

In another study published in 2008 on the American Journal of Clinical Nutrition, they showed that subjects, after losing 10% weight, maintained these compensatory mechanisms even after a year.

In 2011, the New England Journal of Medicine published a study that analyzed hormonal persistence after losing weight.

In this study, 50 patients were given a 500-calorie liquid shakes (51% carbs) for 10 weeks to have them lose weight.

After a year, a hormonal analysis revealed that Ghrelin levels, a hormone that increases appetite and triggers the feeling of hunger, were significantly higher than levels before losing weight!

When they measured the Peptide YY and CCK levels (satiety hormones), they noticed that those hormone levels were lower than the levels after eating a standard meal.

In other words, even a year later, subjects were hungrier and their desire to eat was high. Their bodies were still trying to gain back the weight they lost!

Studies on Eating Extra Calories

In the 1960s, Ethan Sims, a famous endocrinologist, studied overeating at the Vermont State Prison.

He had inmates eat between 4000 to even 10,000 calories a day…wow…while controlling their exercise.

He noticed that some gained weight and then lost it.

He also discovered that inmates metabolic rate increased by 50%, meaning that the body was trying to burn the extra weight off!

In another study published in the American Journal of Clinical Nutrition in 1992, they took volunteers and overfed them by 50% for 42 days and then monitored them for six weeks.

They were given a 46% carbohydrate diet. A lot of carbs!

All of the volunteers gained weight during those six weeks and then lost it after they stopped the diet, except for one fellow, though.

So, there appears to be a set weight that the body wants to be at.

If you go above that weight by increasing your intake of calories, the body will try to bring it down by increasing its metabolism to burn more calories.


…if you cut down in calories and go below that set weight, the body tries to bring that weight back up by slowing down its metabolism to burn less energy and increasing hunger to get you to eat more.

In average, a 10% increase in weight lead to a 16% increase in energy expenditure whereas a 10% decrease in weight caused a 15% decrease in energy expenditure.

The body is smart, in a sense that if it’s not receiving enough food, it will try to shut down to reduce the energy expenditure and also increase hunger to get you to eat!

It is a survival mechanism!

The truth of the matter is that virtually all studies of semi-starvation regimes of low-fat, calorie-restricted diets DO NOT WORK.


When lowering the caloric intake, you lose weight initially, and as you lose weight, the body decreases its energy expenditure to burn less calories and make up for the loss.

At the same time, the body also increases hunger.

You now regain weight and as a result, you eat even less calories in an effort to keep your weight down.

This cycle continues until it becomes intolerable. And when the you cannot take it anymore, you are blamed for not having enough will power.

Losing weight by lowering calories is difficult to accomplish because it fights the body’s own survival mechanisms that have evolved to precisely minimize the effects of the reduction in calorie intake.

Now you know why you plateau when dieting.

Cutting calories works in the short term but not in the long term. It’s not sustainable. It’s not the reason why we’re obese.

Let’s take a look at a better explanation of why we gain weight.

Weight Gain as a Hormonal Imbalance

Insulin Resistance handwritten on a note pad

Now things will turn interesting!

This theory holds that insulin and, to a lesser extent cortisol, act as a regulator as how many calories you burn with your basal metabolic rate and how many you keep in storage (fat).

Insulin was discovered in 1921, and not long after, it was used as a fattening agent.

Not long after that, in 1923, insulin was successfully used to fatten chronically underweight children.

In the 1930s, insulin was also used in Europe and the USA for pathologically underweight patients.

Patients who underwent these insulin treatments along with high-carbohydrate diets gained as much as 6 pounds per week.

Again, let’s take a look at a few studies that elaborate on the direct relationship between insulin and weight gain.

Here’s a list of some of those studies and a few highlights.

  • In this study, for 6 years, they measured weight gain on 1246 adults of 18 to 39 years of age with Type 1 Diabetes. They assigned two groups randomly. One group received 1 to 2 injections of insulin a day (conventional therapy) and the other group received multiple doses of insulin daily (intensive therapy). They realized that the intensively treated patients gained significantly more weight than the patients treated conventionally.
  • In this other study, they looked into weight gain during insulin therapy in patients with type 2 diabetes. They showed that intensive therapy with insulin induced weight gain.
  • In this study, 14 type 2 diabetes patients treated for six months with an intensive insulin therapy of 100 units per day gained an average of 8.7 kgs. (19 pounds). Patients also decreased their caloric intake from 2000 to 1700, 300 calories per day. So, even though they were eating less, they were still gaining weight.
  • This study shows that the higher the doses of insulin, the higher the weight gain.
  • In this other study they showed that combining Sulfonylurea, a drug that increases insulin levels, with insulin, a higher weight gain was achieved compared to patients who were just taking insulin.
  • Dapagliflozin is another drug that works by having kidneys get rid of excess glucose through urine. In this study, the group that was taking insulin gradually gained weight whereas the group that took the dapagliflozin drug didn’t.

Drugs that increase insulin levels cause weight gain and drugs that don’t raise insulin levels don’t cause weight gain.

The more insulin received, the more weight patients gained.

Interesting facts…

…Type 1 diabetics can’t produce much insulin and this lack of insulin leads to rapid weight loss REGARDLESS of how many calories they eat.

When these type 1 diabetics are given insulin, they gain their weight back.

In fact, diabulimia is the name given to an eating disorder in which type 1 diabetics reduce their insulin dose to lose weight.

Likewise, cortisol, a steroidal stress hormone, also induces weight gain

As you may know, people on steroids gain weight!

Also, people with Cushing’s syndrome, a condition characterized by the over production of cortisol, gain weight. On the other hand, the underproduction of cortisol is called Addison’s disease and this condition is notable for causing weight loss.

What Makes People Fat?

What Makes People Fat?

As you saw, it’s not about overeating, having too many calories, or exercising too little. It’s HORMONES!

Obesity is a hormonal dysregulation of fat! And those hormones are predominantly insulin and, to a lesser extent, cortisol.

Insulin is your fat storing hormone. Too much of it keeps your body in fat storing mode.

The presence of insulin suppresses fat burning hormones. They both can’t work at the same time. If one is high, the other one is low.

Your insulin level sets your body’s weight. High insulin levels tells your body to gain weight. So, obesity (high insulin levels) leads to eating too much and exercising too little, not the other way around.

It’s NOT the calories. People on a Ketogenic Diet, which consists of high fat, moderate protein, and low carbs lose weight. And guess what? A gram of fat has more than double the amount of calories than a gram of carbohydrate.

The other big difference is that fat doesn’t spike your insulin. Refined carbs do!

Check out this 8-minute video by William Davis, MD and author of the #1 New York Times Bestseller Wheat Belly. In this video he gives other details about why you should not worry about calories.

YouTube video

Now, the question is what foods are contributing to your weigh gain?

Let’s see that next.

What Foods Are Making Your Belly Fat?

Unknowingly, it is our daily weight gain diet that consists of fattening or refined carbohydrates.

In other words, the foods that make you gain weight by spiking your insulin levels are the sugary and starchy foods and anything made with flour!

It is about the constant consumption of refined carbohydrates, several times during the day, that leads to insulin resistance and results in constant high levels of insulin levels high.

  • Bread and everything made with flour
  • Cereals, including breakfast cereals and milk puddings
  • Potatoes and all other white root vegetables
  • Foods containing too much sugar
  • All sweets

Insulin adjusts your body’s weight. A high insulin level tells the body to get fat and as a result, calories and energy expenditure are adjusted to meet that weight goal.

Now that you better understand what makes you gain weight, it is easier for you to plan how to lose weight!

Want to Learn More?

Weight Gain and Obesity are driven by Hormones, like insulin, and only by understanding the effects of your diet and lifestyle on your hormones, you can get to the root of the problem and get a hold of it.

The Obesity Code by Dr. Jason Fung is an awesome resource to understand why you gain weight and how to get rid of it.

The Obesity Code - Unlocking the Secrets of Weight Loss (Book 1)
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The Obesity Code - Unlocking the Secrets of Weight Loss (Book 1)
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Now, I’ll pass it on to you.

Anything new that caught your attention?

Let me know in the comments below.

Thank you for sticking around!

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