For most of us humans, it’s natural to label things as either good or bad, but sometimes this is a dangerous way of thinking. That is certainly the case with the hormone insulin. Those wanting fat loss call insulin the “bad” hormone because it inhibits fat burning, promotes fat storage and makes us fat. On the other hand, those who want muscle growth consider insulin to be the “anabolic holy grail.”
So which is it? How can this hormone be a chubby guy’s nemesis and a skinny guy’s best friend? First, a little education on the hormone insulin.
What is Insulin ?
Insulin is an anabolic hormone. Many researchers agree that it’s more anabolic than growth hormone. However, it’s indiscriminately anabolic, meaning that insulin doesn’t care whether it stores excess calories as muscle or body fat. Just as with a Bill Belichick coached team, the hormone is just doing its job. And its primary job is to maintain safe and steady blood glucose levels of around 80-100 mg/dl.
When blood glucose (blood sugar) levels rise above 100, insulin is secreted by the pancreas in order to grab the extra glucose out of the blood and take it to a storage depot for safe keeping. There are 3 storage areas in this body that will house extra glucose:
- Muscle glycogen
- Liver glycogen
- Adipose tissue, i.e. body fat
Our preference would always be that it goes to muscle tissue or the liver, but the reality is that insulin will take the extra sugar to wherever you program it, because that’s its job and it does it extremely well. So, how does one “program” insulin? Well, that is an excellent question and it is all about insulin manipulation. But before going there, we need to understand some more about insulin.
4 Insulin Benefits
1. Insulin Builds Muscle
It actually stimulates protein synthesis, which promotes muscle growth, by directing your ribosomes to make more protein. Muscle is made from ribosomes, which are made from protein. Here is a quote from Guyton and Hall’s Textbook of Medical Physiology:
“In some unexplained way, insulin ‘turns on’ the ribosomal machinery. In the absence of insulin, the ribosomes simply stop working, almost as if insulin operates an ‘on-off’ mechanism.” Thus, insulin is required to build muscle.
2. Insulin Inhibits Catabolism
It inhibits the breakdown of muscle, which is known catabolism. The anti-catabolic power of insulin is just as important as its anabolic power. On a daily basis, the body synthesizes some protein and breaks down some protein. To build muscle, you must synthesize more protein than you catabolize. And if you catabolize more muscle than you build as you age, you will grow weaker and less healthy. It’s a nasty condition called sarcopenia.
3. Insulin Transports Amino Acids into Muscle Cells
It actively transports the BCAA’s (branched chain amino acids) directly into muscle cells. BCAA’s are directly escorted into muscle cells by insulin, and these are essential for building muscle.
4. Insulin Increases Glycogen Synthase
Finally, insulin increases the activity of glycogen synthase, which is an enzyme that stimulates glycogen formation. In other words, it aids in the storage of glucose in muscle cells, thereby improving performance, recovery, and the size of your muscles.
5 Negative Insulin Effects
Insulin Inhibits Hormone-Sensitive Lipase
Insulin inhibits an enzyme called hormone-sensitive lipase, which is responsible for breaking down adipose tissue (body fat). So, if you are not able to effectively break down stored fat, and turn it into a form that can be burned, you’ll never get leaner, no matter how much you lift or how many miles you run. This is basic hormone science.
Insulin Decreases Utilization of Fat
It also decreases fat usage for energy, thus making the body rely on carbs for energy. Although that’s not good for our body composition, it is very logical since insulin’s main function is to get rid of extra glucose in the blood. And insulin will accomplish this by both storing carbs and burning carbs.
Insulin Increases Fatty Acid Synthesis
Insulin increases fatty acid synthesis in the liver, which is the 1st step in the process of gaining body fat. This depends on the availability of excess carbs, meaning the amount of carbs over what your body needs for immediate energy.
Insulin Activates Lipoprotein Lipase
Lipoprotein lipase breaks down triglycerides (free floating fatty acids in the blood) into absorbable fatty acids which are quickly and easily soaked up, converted back into triglycerides, and stored as body fat. While it’s good to break down triglycerides, it’s not good if they are just going to be converted back to body fat, and this is what happens when lipoprotein lipase is activated.
Insulin Promotes Glucose Transport into Fat Cells
It increases the movement of glucose across fat cell membranes and into the fat cells. The breakdown and burning of fat for energy is increased in insulin’s absence.
As you read through this section, remember always that insulin is like a New England Patriot…..just doing its job. And that is to remove excess blood glucose from your bloodstream to keep you healthy.
Fat Loss/Muscle Gain Continuum
Decide where you want to be on this continuum.
I want to Lose Fat…………………………………………………………………………………………….I want to Build Muscle
- I want to Lose Fat – If your goal is strictly fat loss, then your tactical objective is to decrease your levels of insulin throughout the day, with the one exception being around your workout. It’s important to initiate some insulin secretion around workout time, in order to stop training-induced catabolism, and to shuttle glucose and amino acids into the muscle cells. Otherwise you’ll simply find yourself in a state of losing valuable muscle and hampering your body’s ability to burn fat.
- I want to Build Muscle – If your primary goal is muscle-building, then your tactical objective is to have high levels of insulin throughout the day, especially around workouts. This will help take advantage of the extra permeability of muscle cells at that time to suck up insulin and all that comes with it, such as glucose and BCAAs.
So then, is there a middle spot on the continuum for those who want to Gain Muscle and Lose Fat?
According to the latest science, researchers now believe that the “insulin switch” can happen in just minutes, unlike what was previously believed (that it took 24 hours). If we accept this as true, then effective insulin manipulation can take place throughout the day, and that then makes it quite possible that we can gain muscle and lose fat simultaneously.
What you would do is to plan your day to have periods of time focused on fat-burning and periods of time focused on muscle-building, as such:
- Increase the amount of insulin you secrete around your workouts, especially when it’s strength training. This means consuming pre-workout carbs and it means consuming post-workout carbs.
- To encourage maximal fat-burning throughout the rest of the day, keep insulin levels as low as possible.
In summary, it’s all about “flipping the switch.”