The key to understanding weight loss lies deep within your body, in the hormone insulin. Understand how it works and you will be able to conquer your inability to lose weight, explains Cyrus Khambatta, Ph.D., co-author of Mastering Diabetes, The Revolutionary Method to Reverse Insulin Resistance Permanently in Type 1, Type 1.5, Type 2, Prediabetes, and Gestational Diabetes, with his co-author Robby Barbaro. The authors want to help you understand the role that insulin plays in your body, your weight-loss journey, and your life.

In the world of weight loss, the general perception is that it's impossible to lose weight and keep it off. As medical professionals who have treated people struggling with their weight, or have diabetes, pre-diabetes, and other metabolic disorders, we have seen it all. And the most common complaint among our patients is: "I've tried every diet on the planet and nothing works."

Is this true? Is losing weight and keeping it off truly impossible? Why do some people manage to succeed while others spend years yo-yo dieting, finally get frustrated, and give up? The truth is that your body weight is influenced by many physical, emotional, and mental aspects of your life. Blaming your inability to lose weight on a single reason often results in oversimplifying a complex collection of biological processes.

When I started my career to help people with diabetes understand how to eat for excellent health, I never thought that one day I would become a weight loss coach. But helping more than 10,000 people lose weight and keep it off has given me the impetus to deep-dive into scientific research to find out the answer to a simple question:

What do people who are successful at weight loss in the long-term have in common?

From reading thousands of papers about weight loss, insulin resistance, diabetes, and heart disease, one thing has become abundantly clear–in order to lose weight and keep it off in the long-term, it’s essential to understand the role that insulin plays in your body.

Truly understanding how insulin works will not only help you lose weight, it can actually save your life. The problem is that most people misunderstand the role insulin plays, and believe that it is simply a signal to tell the body that there is too much sugar present and to store it as fat. That's an oversimplification that can sabotage your best efforts. Here is the way it works:

The reason is simple: the amount of insulin that your pancreas secretes in the fasting and fed state is one of the most important determinants of your ability to lose weight now and into the future.

More importantly, understanding how to reverse insulin resistance (the underlying cause of high blood sugar present across all forms of diabetes) and become insulin sensitive is essential in understanding how to achieve your ideal body weight for the rest of your life.

What Exactly is Insulin?

In simple terms, insulin is the most anabolic hormone in your body. What this means is simple: insulin promotes more fuel storage and tissue growth than any other hormone – more than testosterone, estrogen, growth hormone, and IGF-1.

When insulin is present in your blood in sufficient quantities, tissues receive a high energy signal that says “this is your opportunity to uptake fuel, grow, and replicate.”

In response, cells in tissues all throughout your body activate thousands of biological pathways specifically designed to uptake and store fuel, synthesize DNA, transcribe genes, manufacture protein, grow larger, and replicate.

Is Insulin Good or Bad?

Since insulin was first discovered in 1921, scientists have known that insulin is an essential hormone, and is critical for optimal health in all mammals. Why then, do millions of people around the world live in fear of insulin and do everything they can to minimize their insulin exposure?

Why do medical professionals and people living with diabetes point their finger at insulin and make claims that “insulin will make you fat,” or that “insulin will increase your cholesterol,” or that “insulin will make you more insulin resistant”? The reason is actually quite simple – the biological role of insulin is one of the most misunderstood concepts in all of human biology.

Here Are Two Things That Are Essential to Understand About Insulin:

(1) Insulin is absolutely necessary for life. If insulin were not present in your body, you would die in a short period of time (likely within weeks or months). Living in an insulin-deficient state for prolonged periods of time is incompatible with life.

(2) Insulin itself does not raise your risk for chronic disease. Excess insulin beyond your normal physiological level is what causes severe metabolic dysfunction, weight gain, and increases your risk for many chronic diseases over the course of time.

Both too little insulin and too much insulin increase your risk of death. However, secreting a normal amount of insulin:

(1) is required for life

(2) is required to control your blood glucose

(3) allows you to lose weight easily and sustainably, and

(4) minimizes your risk for many chronic diseases

So the key is to eat to control the amount of insulin in your body, lose weight, and keep it off.

Do Low-Carb Diets Actually Help You Lose Weight?

Many health professionals will tell you to eat a low-carbohydrate diet to lose weight. While it’s true that low-carbohydrate diets like the Atkins Diet, the Paleo diet, the ketogenic diet, and the carnivore diet can certainly decrease the amount of insulin you secrete and help you lose weight quickly, low-carb diets can become problematic in the long-term.

Many people who eat a low-carb diet find that their appetite decreases significantly. As a result, they eat fewer calories which results in rapid weight loss. Scientists have discovered that low-carbohydrate diets are excellent rapid weight loss tools, but these low-carb diets also have a laundry list of side-effects including:

(1) They make you more insulin resistant, which dramatically increases your risk for many chronic diseases

(2) Are associated with an increased risk of heart disease and chronic kidney disease

(3) Significantly increase your risk for all-cause mortality (death from any cause)

(4) Are difficult to maintain in the long-term, often leading to rebound weight gain

A Low-Fat, Plant-Based, Whole-Food Reduces Your Insulin Exposure

Another extremely effective way to lose weight is to eat a low-fat, plant-based diet complete with as many whole fruits, starchy vegetables, legumes, and whole grains as possible.

When you do this you’ll lower the insulin concentration in your blood and make insulin extremely efficient in both your muscles and liver. This will decrease (but not eliminate) your insulin levels, and stimulate weight loss immediately and into the future.

As you eat more fiber-rich foods, you’ll likely feel satisfied with every meal, because the combination of fiber and water (known as bulk) stretches your stomach, small intestine, and large intestine, which tells your brain to slow or completely shut off your hunger signal.

Scientists have discovered that bulk is the most effective satiety signal in humans and that the amount of bulk in your food is the most important determinant of how satisfied you feel after a meal, and how likely you are to achieve your ideal body weight.

For Sustained Weight Loss, Choose a Plant-Based Diet

The truth is that even though low-carb diets can look attractive from the outside, successful long-term weight loss is associated with a low-fat diet, less energy-dense food, and more fiber-rich foods.

If you’re only interested in rapid weight loss, then a low-carb diet can certainly get you the results you’re looking for. But if you choose to eat this way, don’t be surprised if the weight comes back in the future, and it makes it even harder to lose weight again, and keep it off.

If instead, you’re looking to lose weight and keep it off, then eating a low-fat, plant-based, whole-food diet will help you lose weight consistently and sustainably, and virtually eliminate the risk of a yo-yo.

If you need more proof other than our experience, consider this: A meta-analysis of seventeen observational studies of more than 270,000 people concluded that low-carbohydrate diets increase mortality risk. The authors indicated that a “systematic review and meta-analyses of worldwide reports suggested that low-carbohydrate diets were associated with a significantly higher risk of all-cause mortality in the long run.” The authors further stated that “these findings support the hypothesis that the short-term benefits of low-carbohydrate diets for weight loss are potentially irrelevant.”

So knowing that your goal is to keep insulin efficient, as opposed to low, you need to eat a steady amount of carbs, preferably those that are high in fiber, to allow your body to burn carbs and fat, and not experience the yo-yo dieting phenomenon of losing fast and then gaining it back.

The plant-based approach to a low-fat diet high in whole foods is your best bet to long-term weight loss that sticks.