Insulin and Weight Loss Explained
Explore the world of weight loss long enough and you will hear talk of insulin “spikes”, “levels” and “resistance”. What even is insulin? And what does it have to do with losing weight? Confused? Don’t be – we’re clear up everything you need to know about this crucial hormone and how it relates to dieting.
What exactly makes insulin and weight loss so dependent on each other?
Insulin is very closely connected with burning fat and losing weight. Without reducing insulin there’s almost no way you could burn a substantial amount of fat no matter how hard you exercise and diet.
Even though most people have heard about insulin spikes not being good for weight loss, the average person still doesn’t truly understand why. Here, we will unravel the mystery of insulin, what it does and the part it plays in weight loss.
Insulin’s role in the body
It all starts with you eating. When you eat, the chewed-up food particles get broken down further in your stomach into very small parts and then they pass through your intestines. At this point your body absorbs and breaks down those nutrients and calories again and dumps them into your bloodstream.
These broken-down nutrients can’t just jump into the cells that need them for their daily functions without some kind of help. That’s where insulin comes in.
Insulin is a hormone secreted by your pancreas and it gets released into your bloodstream when your body senses that blood sugar has increased. (Blood sugar increases because whenever you eat any type of carbohydrate (starches, fruits, milk, sugars etc.), your body breaks it down into simple sugars. These get absorbed into the blood stream.) Insulin’s job is to help remove the sugar from the blood into the cells to be used for energy.
Very high blood sugar levels (hyperglycemia) is bad for you. It can damage the vessels that supply blood to vital organs which can increase the risk of heart disease and stroke, kidney disease, vision problems, and nerve problems. Insulin acts as a bridge between your cells and the sugar in your bloodstream. Without insulin your blood sugar would be dangerously high. This is actually pretty much what Type-2 diabetes is. When people are insulin-resistant (which means that insulin isn’t doing its job) they usually wind up being labeled as a Type-2 diabetic which means that they need an external source of insulin. For example, either an injection or a pill to get that blood sugar down.
So what does all this have to do with fat loss and weight gain?
Insulin and weight loss
So, insulin is the hormone that tells our cells to pick up glucose from the bloodstream. It is also the major energy storage hormone in the body. It tells our cells to store energy, either as glycogen or fat.
Whether you eat pasta, bread, brown rice or drink soda, all of it will eventually be broken down into simple sugars floating around in your bloodstream. The only difference is that whole high-fibre carbs like brown rice will take a lot longer to digest. This means that the sugar will be released into your bloodstream at a much slower pace. Compare that to a can of soft drink or a chocolate bar where the sugar will pretty much be released all at once.
When sugar released into your bloodstream slowly you give your body a chance to actually use it over time so you won’t require quite as much insulin. This leads to less sugar being stored as fat. Before insulin starts storing blood glucose into fat cells, it will first store as much of it as possible into your liver for later use.
Unfortunately, the liver can only hold a limited amount of blood sugar and then the excess is dumped off into your muscle cells. Now your muscle cells can hold more of this glucose than your liver can. However, they also have their limit. Even the most muscular person on the face of this planet is going to have a limit of how much of this blood glucose can actually be used by the muscle cells.
Once that limit is reached, we hit “spillover”. Here, your body starts to store sugar from carbohydrates in your diet as glycogen or fat in your cells. It does this to lower the sugar found in your bloodstream back to normal, safe levels.
“Insulin shunts sugar to fat. Insulin makes fat. More insulin, more fat. Period.”
Glucagon and weight loss: turning fat into fuel
So, insulin is an anabolic hormone that causes weight gain and growth. The opposite of insulin is a peptide hormone known as glucagon which is released when your blood sugar drops too low.
When this happens, glucagon (just like insulin) goes in and acts as a bridge between the stored energy in your cells and your bloodstream except it has the inverse effect. So it pulls energy from your cells and dumps it into the bloodstream.
However, before your body will start pulling fat from fat cells for energy, it will first pull stored glucose from your liver and your muscle cells.
This is why so many low carb diets work when you don’t have that many carbs. It’s easy for your body to use up the carbs stored in your muscles in your liver and then proceed straight to burning more fat for energy. This is the same reason why the ketogenic diet works except an added benefit to the ketogenic diet is that your body becomes more efficient at using fat for energy which means more fat will be burnt.
The insulin-glucagon see-saw
When insulin is up, glucagon is always down and vice versa. This means that when insulin levels are elevated, you’re not going to be burning any fat until glucagon rises and that will only happen when blood sugar falls (i.e. after insulin has done its job, after sufficient fasting or on a ketogenic diet).
In fact, insulin will block your body from burning fat. (Insulin has also been shown to block leptin which is a hormone that lets your body know that you’re full – leading to over-eating).
Consistently high levels of insulin are usually associated with leptin resistance. This means your body is becoming resistant to the hormone that’s supposed to signal to your brain that you’re full and to stop eating.
So, high blood sugar levels and high insulin levels, is a vicious cycle that usually results in weight gain. The question is, what do you do to lower insulin and blood glucose levels to burn more fat?
Why keto and low-carb diets works
The first thing to do to burn fat and lose weight is limit your carbohydrate (and sugar) intake.
Fat and proteins won’t spike insulin quite as much carbs. They’ll still spike insulin levels but it will be less. Low glycemic carbohydrates are often suggested as alternatives to refined simple carbohydrates. Low GI foods are slow-digesting carbohydrates and so do not cause large insulin spikes.
As blood sugar levels fall, glucagon is released to pull energy back out of your cells to normalise your blood sugar level.
The secret to weight loss? Restrict carbs and sugar
So you see how this works?
- Sugar and carbohydrates (which turn into sugar in your body) increases the sugar level in your blood
- Your body produces insulin. Insulin moves sugar out of your bloodstream and into your cells where it can be used for fuel.
- But there’s a limit to how much energy your cells can store. Excess sugar will be stored as fat in cells.
- Glucagon is insulin’s opposite. It pulls energy out of cells. But glucagon will only make an appearance when blood sugar levels are low. As long as you are consuming carbs and sugar, glucagon does not appear, i.e. fat stays in your cells.
This is why you can still gain fat eating healthy foods. Fruit, quinoa, juice and sweet potatoes can all still turn into fat. What matters is your blood sugar and insulin levels and these are determined by the amount of carbs and sugar you consume. Obviously, it’s going to benefit you a lot more to have the brown rice than having a can of cola. However, remember that spillover into your fat cells can still happen even with the healthy food.
A better approach to weight loss
Forcing your body to burn fat by restricting carbs is important. It’s not the whole picture, but it’s a large part of it. Limit your total daily intake and go for a limited amount of low-glycemic carbohydrates. These don’t spike your insulin quite as much and you’ll feel better on them. Alternatively, try the keto diet.
And from the exercise standpoint you want to build some muscle to be able to absorb more blood sugar. With more muscle, you’ll use more of this blood sugar as fuel rather than storing it as fat.