Insulin: shots that diabetics have to take whenever they eat. Right? Well, not exactly. Surprisingly enough, insulin actually plays a vital role in the delivery of building-block proteins—from your main protein food sources, and from your protein shakes—to your muscles. That’s why keeping your insulin levels tightly controlled is one of the best ways to boost both fat loss and muscle gain.
Insulin’s function is to get glucose—your body’s primary fuel source—from your bloodstream into the cells of your muscles. But insulin also plays another vital role: it is one of the body’s main tools in muscle building. And it’s a big part of fat retention: insulin control should form the keystone of the arch that makes up your muscle-building and fat-loss diet regimen.
Insulin and Your Muscles
Insulin is not the kind of protein you’ll find in a protein shake; rather than being used by your body primarily as a building block for muscle, insulin works as a “functional” hormone. It functions more as a signal controller, like a traffic light, than like a pile of bricks for your body to build into muscles.
The cells of the muscle each contain a series of receptors designed to recognize insulin. The insulin “docks” with these receptors, like a key that opens a lock. Once this ‘key’ has entered the ‘lock’ of the muscle cell, the muscle cell opens its walls to absorb the glucose, amino acids, creatine—whatever you’ve just eaten—allowing them enter those muscle cells.
Insulin and Fat Retention
The healthy body naturally releases insulin whenever you eat. This signals to the body that nutrients are coming down the line, and to be ready to absorb them. Your body always seeks homeostasis, so when you eat, you stop burning fat. You’ve just flooded your body with nutrients, so it no longer needs to eat away at those fat cells to get the fuel it needs.
Like muscle cells, when fat cells dock with insulin, they start collecting nutrients to be stored for later use. This is why it’s generally a bad idea to let your insulin levels rise many times in the course of a day. It might help with muscle building, but it’s also going to decrease your rate of fat burning.
Generally, if the insulin is flowing properly and the nutrients are being absorbed, by the time your insulin levels go back down, most of those nutrients are out of the bloodstream and in the muscle tissue.
Two things happen at this point. Blood sugar levels fall, and you experience a “crash.” This can happen either because your sugar tolerance is impaired for some reason, or because you flooded your body too heavily with glucose. This crash and attendant low blood sugar are the essential elements of what we call “hypoglycemia.”
This tends to precipitate a vicious cycle. You crash, and your energy levels drop down to what feels like about zero. You get really, really hungry, and most people in that situation reach for more simple carbohydrates. You start the cycle all over again. This causes a lot of fat buildup.
Control Your Insulin, Control Your Physique
Insulin is really a double-edged sword, since it’s great for muscle building, but it also helps build up fat. Since you want to maximize your muscle gain while avoiding retaining fat, mastering the art of controlling your insulin levels throughout the day is one of the keys to sculpting your body the way you want it. Here’s how to do it.
This is not as complicated as it sounds. There are a few different types of carbs, as you’re probably aware, and choosing wisely which to eat and which to avoid are fundamental to responsible insulin control. Two basic types are important here. There are carbs with a high glycemic index, or “high GI,” and carbs with a low glycemic index, or “low GI.” GI refers essentially to how fast your body is able to transform those carbs into glucose.
Foods with a high glycemic index pass quickly into the bloodstream. Eating a lot of this kind of food floods your blood with glucose. When this happens, there’s an attendant spike in insulin levels. Foods with a low glycemic index are much more time-consuming to digest, so they tend to gradually enter the bloodstream. This keeps your insulin from rapidly spiking.
The basic rule is that simple sugars—like regular old white sugar—have a high glycemic index, while complex carbs—like sweet potatoes—have a low glycemic index. There are a few other factors that determine a food’s glycemic index, but those will be exceptions, rather than the rule.
For example, fruit is extremely high in fructose, a simple sugar. But most fruit—again, with exceptions—is considered a low-GI food.
There are a couple reasons for this. Fruits contain a lot of fiber, which slows digestion. All that fructose gets transmitted slowly, since the digestive system also has to work through the fiber as well. Further, fructose itself isn’t muscle fuel. The body must first convert it into glucose. This isn’t the case for something like table sugar, so in general the sweetness of the fruit, the sugar, doesn’t spike insulin levels the way table sugar or candy would.
Some of those “exceptions” include fruits that don’t have a lot of fiber, like melons or dates. These are typically high-GI foods.
Then, there are exceptions to the low-GI rule as well. Potatoes contain primarily complex carbohydrates, but they tend to be very quickly digested, so those complex carbs get distributed through the bloodstream much more quickly than those of most fruits. This applies to several other kinds of complex carbs, including white bread, and the most commonly-consumed types of white or bleached rice.
Most of the time, stick with carbs that have a low glycemic index. Remember that you want to avoid insulin spikes, so eating these low-GI foods helps keep insulin levels constant. You want to maintain your energy level, as this will help in the slow but consistent burning of fat.
You’ve probably seen bodybuilders load up on high-GI foods right before working out. They reason that for a workout, they want fast energy, and indeed, that’s precisely what they get. This is all well and good, until one comes to the end of the workout; you know, the sets that “really count.” By that time, most of those high-GI foods have already reached the muscle tissue; you’re in the “crash.”
For this reason, nowadays it’s considered best to load up on complex carbs (low-GI foods) for continuous energy, rather than trying to spike your energy levels and get your workout done before the crash hits.
If carbs before a workout are part of your routine, add to your protein shake about 30 grams of low-GI carbohydrates. This will give you the energy you need, without overloading your body with glucose, so your energy levels will be sufficient to get the high-intensity workout you’re after, without a crash.
Keeping your insulin at a relatively low, constant level has a few nice side effects. It has been shown in studies on animals that keeping a low and consistent insulin level increases longevity. In fact, the animals in the study with the lower insulin levels lived up to 50% longer! Science is working to understand why this might be the case, but it’s been hypothesized that cells degrade when they’re constantly having to open and close their nutrient gates, rather than staying in relative absorption stasis over the course of your lifetime.
Bodybuilders build mass and burn fat, right? Obviously. But you may be focusing on one or the other of these, depending on where you are in your development.
This will play a role in deciding when and if to load up on high-GI foods and simple carbs. If you’re primarily focused on building mass, then you may stand to gain (muscle mass, that is) from consuming a reasonable quantity of high-GI foods immediately after waking up.
“Breakfast” is quite a literal name. You’re “breaking” your “fast.” If you get anything like as much sleep as you’re supposed to, your body wakes up recovering from between six and eight hours of fasting. At this point, falling levels of glycogen in the muscle tissues and liver have signaled your body to start eating away at muscle tissues to generate fuel. So, about 30 grams of high-GI carbs early in the morning will give you a little glycogen spike, to stop your body from turning that precious muscle mass into fuel.
Now, this next recommendation isn’t going to make sense at first, but keep reading for an explanation. Fruit makes an excellent early-morning meal, because of all the sugar.
But didn’t we just say that fruits are actually low-GI foods? Yes and no.
The purpose of the high-GI early-morning feeding frenzy is not primarily to spike your insulin levels. This will happen, but the primary purpose is to boost your glycogen levels. One of the places where glycogen performs its signaling activity is in the liver—and this is precisely where fructose goes to be transformed into glucose, which your body can use for fuel. So, when all that fructose hits your liver, glycogen levels spike, and it cuts off the muscle-eating process.
But, like everything else, falling glycogen levels can provide a benefit. Along with eating away at muscle, your body also burns fat for fuel. For that reason, if you’re more concerned with burning fat than with gaining muscle, skip any carbs early in the morning. You can keep your muscles from deflating with a protein shake.
There is one more good time for high-GI: right after an intense workout. Make sure it goes with a protein source, like a Sports Foods protein shake, since the purpose of this simple carb load-up is to spike insulin levels and get all those amino acids pumped into your muscle tissue.
This fast-digesting food will restore all the muscle glycogen you used to complete your high-intensity workout.
The Power of Protein
Studies have shown that fast-digesting protein contributes to insulin spikes. In fact, if you eat a protein-heavy meal or consume a protein shake alongside some high-GI foods, your insulin levels will soar even higher than they would if you just loaded up on the simple carbs, sometimes twice as much, leading some researchers to suggest that proteins like whey can be as much of an insulin-booster as high-GI foods themselves.
Doesn’t this go against the whole theory of maintaining low insulin levels to prevent interfering with fat loss?
Strangely enough, studies show that whey protein actually aids fat loss. While it does appear to spike insulin levels, the effects of the insulin spikes are not the same as they would be if they came from simple carbohydrates. It may be tied to the fact that leucine, the primary branched-chain amino acid present in whey protein, increases insulin sensitivity in muscle tissue.
This means less hunger, so you don’t load up on simple carbs over and over again and end up blunting your fat-burning.
So there’s not much to worry about when considering the insulin spikes from whey protein. The one exception to this is if you are trying to drop off a few final pounds of fat from some stubborn areas, you may want to trade in the whey protein for casein protein. Micellar casein in particular does an excellent job, as this is a milk-based protein that doesn’t affect insulin production in the same way that whey proteins, heavy in leucine, tend to do. You can replace whey protein shakes with casein protein shakes whenever you’d normally have a whey shake.
This way, you’ll still get all the protein you need to your muscle tissues, without blowing your insulin levels off the charts and slowing down fat burn. If you’re looking for more of a balance, combine the two proteins: this will give you the best of both worlds while minimizing the insulin effects of whey.
Insulin Absorption and “Fake” Insulin
While we’re not going to recommend you take synthetic insulin, there are some supplements that exist that can help your muscles absorb the nutrients they need without having to rely solely on insulin itself to do the job, with all the possibly negative side effects on hunger and fat burn that it brings. Look into alpha lipoic acid, or ALA.
ALA improves the action of the insulin that’s already in your bloodstream, so the same amount of insulin can do more work at the cellular level. For optimal results, keep your ALA intake somewhere in the 300-500 mg range. Add it to your normal protein shakes and post-workout carbohydrates. This way, you get a healthy insulin level, while maximizing its effectiveness. With enhanced insulin performance, you’ll improve your regeneration and muscle growth with each and every workout.