Back to the Basics: Insulin - Mind And Muscle

guy curling dumbbellby: Glen Neilson

What’s the first thing that comes to mind when you hear the word ‘insulin?’ Maybe it’s diabetics, fat gain, or a number of other things. The truth is it’s these things and much more. In this article I will discuss what insulin is and how it works, and why diets try to control it. I will also compare the glycemic and insulin index to see how we can use these tools. Lastly I’ll explain insulin’s effects on the brain and the dreaded ‘low-carb limp,’ plus list some points of interest.

What insulin is and how does it work

Insulin is a hormone produced by the beta cells of the pancreas in response to raised blood glucose (sugar) levels. Its whole purpose is to regulate the metabolism of glucose and other nutrients.

When your body goes without food for a time you develop a sensation of hunger, which generally leads you to consume a carbohydrate (or any macro nutrient) meal. These carbohydrates become converted to sugars in the blood, which causes the release of insulin. The insulin allows sugars to leave the blood and enter the cells of the body; this leads to a change in brain chemistry and this change generates a feeling of satisfaction. Over the course of hours, the insulin-to-blood sugar ratio will once more change and brain chemistry will again cause a sensation of hunger.

For a more illustrated and in-depth look, let’s say you eat an apple. Glucose (a simple form of carbohydrate, converted form the complex carbohydrates in the apple) will pass through your small intestines and into your blood (now called blood glucose). Your body will sense this raise in blood glucose and will signal your pancreas to release insulin, which allows and helps carbohydrates, proteins and fats to enter cells.

This is necessary because cell membranes are made up of a fat matrix. Along this fat matrix are small door-like portals called ‘protein carrier molecules.’ Through these “doors” insulin carries the nutrients into cells in a process called ‘facilitated diffusion.’ With this basic knowledge we can now look at how diet affects blood glucose levels and learn how to use insulin to our advantage.

Why try to control insulin through diet?

The pancreas secretes insulin, with the highest levels peaking around 6 a.m. The pancreas also releases insulin 50 percent faster in the morning. This means that even if you eat the same foods at different times of the day, the amount of insulin you secrete varies. In fact, a morning insulin shot reduces glucose 40 percent more than an afternoon one. (Though I don’t recommend it, this is something to keep in mind for bodybuilders who choose to ‘supplement’ with insulin).

The first question should be “why would we want to manipulate insulin?” Permit me to explain. As shown above in the preceding paragraphs, insulin is what “carries” nutrients into our cells. For example, imagine drinking a meal replacement after working out and not having insulin. This would cause high levels of blood glucose (hyperglycemia), as the nutrients could not pass through the fatty matrix cell membrane without their “carrier.” Eventually the blood glucose would be excreted through the urine and wasted. Therefore your cells would not receive fuel and wouldn’t grow—end of story and end of life (hence the need of diabetics to inject insulin). Of course the more nutrients that enter the cell the larger it will grow, be it a muscle or fat cell.

If you read any of the diet books on the shelves of your local super market you’ll see that they all revolve around the principle of reducing insulin. Why would someone want to do this? The theory is, by reducing insulin through changes in diet, less insulin will be released and less fat stored. Think of the portals on your cell membranes as an intersection, and insulin as the stoplight. While insulin is present it’s a green light for nutrients to enter the cell and a red light for stored energy to leave the cells. Therefore nutrients are either going in or going out. This is why most find it very difficult to gain size and lose fat at the same time, hence the need for bodybuilders to bulk up and then cut or vice-versa.

Glycemic index

Most if not all of us have heard about the insulin index. Countless books have been written about it and are some of the best sellers on the market. The premise behind it is that certain foods cause blood sugar to rise higher and faster than others. The thought is that if you avoid these ‘high glycemic’ foods, blood glucose levels won’t rise as high, making you releases less insulin, allowing you to store less fat. This looks great on paper but what many of us don’t know is how they obtain these ratings. Here’s how it’s done. An amount of food containing 50 grams of carbohydrate is given to a volunteer to eat. For example, to test boiled spaghetti, the volunteer would be given 200 grams of spaghetti, which supplies 50 grams of carbohydrate. The volunteer’s response to spaghetti (or whatever food is being tested) is compared with his or her blood sugar response to 50 grams of pure glucose.

Do any of you find this a little unusual? Who eats 50 grams of only one food at a time? Most have tomato and meat sauce with their spaghetti, so now what is the glycemic index of the meal?

It’s also advised to avoid carrots because their glycemic index is so high. I want to know who eats 50 grams of carbohydrates worth of carrots without ranch dip, or anything else for that matter. Oddly enough a snickers candy bar is allowed because it has a lower glycemic response. Interesting to think that carrots are ‘bad’ and snickers are ‘good.’

Graham crackers filled with partly hydrogenated soybean oil (trans fats) and sugar are better for you than whole grain oat cheerios; milk chocolate loaded with saturated fat and sugar is better for you than nonfat yogurt and coca cola is better for you than Gatorade. Like I said, great on paper but ridiculous when applied literally to your diet.

In case you cared

Though I’m not a big fan of the glycemic index, it’s not totally useless. For that reason I’ll list the blood glucose responses of commonly eaten foods that are thought to be healthy but are wolves in sheep’s clothing.

Food Plasma Glucose, mg/100ml
Cheerios At 45 minutes after ingestion, over 100
Quaker Instant Oatmeal Peaches and Cream At 30 minutes after ingestion, nearly 120

These two foods are listed to show you how a food that looks good for you may actually be harmful. Cheerios is touted as ‘toasted whole grain oat cereal,’ ‘part of a heart healthy diet,’ and we are told that ‘the soluble fiber in cheerios can reduce your cholesterol!’

Here’s what they don’t tell you. The first problem is that the major ingredient of cheerios is modified cornstarch! Of course they hid this in the ingredients under ‘whole grain oats’ (hardly). Secondly, of the 22 grams of carbs, 3 are dietary fiber. Of those 3 only 1 gram is soluble fiber. One measly gram! It takes at least 3 grams (according to the small fine print on the cheerios box) to help with heart disease. You might as well just eat a sheet of paper and get more fiber.

Bagel At 30 minutes after ingestion, 115
Bagel w/peanut butter At 45 minutes after ingestion, 100

Here we see how bad a bagel can be. It looks like if we add peanut butter we lower blood glucose levels by 15mg/100ml and delay its time to peak for 15 minutes. The only problem is its effects on insulin levels. As will be explained below, adding fat with carbohydrates increases insulin secretion even though plasma glucose response is reduced!

Insulin index

The insulin index score is a ratio based on insulin levels found over 2 hours after consuming 1000 calories of the test food to 1000 calories of white bread. Now we are talking calories to calories (though that much bread is an unrealistic representation of a meal). On some foods tested, the glycemic index was higher than the insulin score, while on others the insulin score was higher than the glycemic index. For example: pasta, rice, and potatoes have glycemic indexes far greater than insulin scores, yet beef and fish have insulin scores far higher than their glycemic index. What does this tell us? It tells us that our blood sugar level isn’t the only thing that determines the amount of insulin released.

Protein rich foods produce a low blood glucose response but it does not follow that there is a correspondingly low insulin response. The glycemic index does not consider concurrent insulin responses, only blood sugar responses. For example, protein rich foods or the addition of protein to a carbohydrate rich meal can stimulate a modest rise in insulin secretion without increasing blood glucose concentrations. Adding fat to a carbohydrate rich meal also increases insulin secretion even though plasma glucose response is reduced. So protein and fat rich foods also induce substantial insulin secretion despite producing relatively small blood glucose responses.

Insulin on the brain

When you go into ketosis your body reacts as if it’s starving and switches over to releasing fat stores for fuel. This sense of starvation acutely suppresses reproductive function by inhibiting the release of gonadotrophins. This occurs because of reduced neuron signaling by insulin in the brain. (Note: it was thought that the brain was insulin insensitive because its ability to use glucose does not require insulin. Research however demonstrates that insulin is transported across the blood brain barrier and that insulin receptors are concentrated in brain areas involved in energy and hormonal homeostasis. More on this later.)

The ‘low carb limp’

So now we see why low insulin diets are very popular these days. Just look what diet book is the highest seller and you will see that it’s the Atkins Diet. All of us know at least one person that is on or was on the low-carb road, and we probably saw a tremendous loss of body fat occur. These diets, like most, are usually accompanied by thermogenics of some type—mostly ephedrine and caffeine. An interesting phenomenon that some will experience on a low-carb diet in conjunction with thremogenics is what we call the ‘low-carb limp.’ Those that have experienced this know exactly what it means. It seems that the more sexually attractive you become by dieting low-carb, the less you can sexually function. Throw in a thermogenic stack and erections are almost non-existent.

It appears that an increase of calories in one’s diet does raise anabolic hormones such as insulin-like growth factor one (IGF-1) and testosterone. Now while on a low-carb diet many will notice a loss of appetite. This means a decrease in calories. Could this possibly bring with it a decrease in testosterone? Well, higher levels of testosterone are found with greater carbohydrate intake than with protein. In fact, replacing carbohydrates with protein has shown to decrease testosterone levels!

Now what happens when you cut your carbohydrates? You increase your protein. This decrease in carbohydrates coupled with a lower appetite and higher protein intake equals less calories and lower amounts of insulin-stimulating foods. Thus, less insulin crosses the blood-brain barrier, and less insulin in the brain signals the body that it’s starving. This turns off the release of gonadotrophins.

You are now producing less testosterone; this in and of itself can affect erections (though it has been shown that some hypogonadal men can achieve erections just as easily as normal functioning men can). On top of producing less testosterone, add a thermogenic stack. Not only does this further reduce testosterone levels but also the ephedrine stimulates alpha-receptors. When this happens your body goes into a ‘fight or flight’ response and all non-necessary functions for immediate survival shut down. In regards to insulin, ephedrine and caffeine decrease insulin sensitivity. This causes reduced brain insulin signaling and further inhibition of gonadotrophins. So, long-term use of low-carb diets can significantly reduce testosterone levels, which can in turn lower training tolerance and sex drive.

Points to remember

  • Insulin is good, not bad. It’s not something you want to suppress, just control. Though it can increase fat storage, if you work out and manage your diet correctly you can store the majority of your calories in muscle tissue.
  • The glycemic index is not realistic in regards to how we eat. Though the insulin index is not perfect either, it’s much better and tells us what we really need to know.
  • Insulin does cross the blood-brain barrier and affects energy and hormonal balance in a positive way.
  • Low carbohydrate diets are effective, but have the ability to reduce the release of gonadotrophins (i.e., testosterone).
  • Ephedrine and caffeine are also effective, but have the ability to reduce testosterone and increase insulin resistance.

What to do about it

The role of diet


  • Research has shown a strong connection between the intake of essential fatty acids (GLA and DHA) and reduced insulin resistance. Both human and animal studies show that a dietary intake of EFAs increases the unsaturated fatty acids in membrane phospholipids and makes the individual more insulin sensitive.
  • Prostaglandin E1 makes insulin work more effectively. GLA increases this beneficial prostaglandin. The richest known source of GLA is borage oil (23% GLA). Gamma-linolenic acid (GLA) is also found in hemp oil and evening primrose oil.
  • A high fat diet is not necessarily bad, provided it contains a sufficient proportion of EFAs. Similarly a low fat diet is not necessarily good if it does not provide the body with a sufficient amount of essential fatty acids. A fat-restricted diet will actually lead to an unwanted stimulation of lipid per oxidation and formation of pro-inflammatory substances, involved in the development of chronic degenerative diseases such as arteriosclerosis and rheumatoid arthritis.
  • Not only do we need a sufficient amount of EFAs, we also need the right EFAs in a balanced proportion (two parts of omega-6 to one part of omega-3). In short, we need to reduce the intake of omega-6 oils, except GLA, and increase omega-3 fatty acids, particularly DHA (DHA is plentiful in cold water fish, such as salmon, mackerel, herring and tuna that feed on DHA-rich micro-algae).


  • When amino acids are administered simultaneously with carbohydrate, they strongly potentate the glucose stimulus for insulin secretion. Thus, athletes should consider ingesting both nutrients within a given meal, particularly following a bout of exercise. This may serve to enhance glycogen re-synthesis and favorably impact protein turnover.

The importance of Exercise

Resistance training:

  • Enhances muscle glucose uptake.
  • Enhances insulin sensitivity; this may persist 12-24 hours post-exercise but begins to decline in as little as 1 to 2 days without exercise.
  • It has been shown by a number of papers that resistance training for insulin resistance is better than aerobic training. There are a variety of other reasons too. Resistance training is referring to muscular exercises. If you just do a biceps curl, you immediately increase the insulin sensitivity of your biceps. Just by exercising you are increasing the blood flow to that muscle. That is one of the factors that determine insulin sensitivity. It has been shown conclusively that resistance training will increase insulin sensitivity.
  • It has been found that several months of resistance training leads to a much greater increase in insulin sensitivity than seen in patients who engage in aerobic training. This is attributed to an increase in glycogen storage.
  • It has been shown that bodybuilders, who traditionally employ a high volume style of training, favorably alter glucose tolerance and insulin sensitivity.

A quick warning: Beware of excessive eccentric training:

Muscle damage impairs insulin stimulation of IRS-1, PI3-kinase, and Akt-kinase in human skeletal muscle. Del Aguila, Luis F., Raj K. Krishnan, Jan S. Ulbrecht, Peter A. Farrell, Pamela H. Correll, Charles H. Lang, Juleen R. Zierath, and John P. Kirwan.

To quote their findings:
In summary, the physiological stress associated with muscle damage impairs insulin stimulation of IRS-1, PI3-kinase and Akt-kinase, presumably leading to decreased insulin-mediated glucose uptake. Although more research is needed on the potential role for TNF-alpha inhibition of insulin action, elevated TNF-alpha production after muscle damage may impair insulin signal transduction.

Quasi-legal drugs


  • Though controversial, it has been proven in studies that as people gain weight, they develop more fat cells.
  • Metformin works by increasing the number of muscle (and possibly adipocyte [fat cell]) insulin receptors and the attraction for the receptor. It does not increase insulin secretion, it only increases insulin sensitivity. Therefore, Metformin is not associated with causing hypoglycemia. This activity reduces insulin levels by increasing the sensitivity of peripheral tissues to the effects of insulin by restoring glucose and insulin to younger physiological levels that may cause weight loss and most certainly a decrease in the body’s total fat content.
  • Metformin has been shown to cause a reduction in total cholesterol, appetite, weight, and the body’s total fat content.

Parlodel (Bromocriptine)

  • Stimulator of dopamine receptors, inhibitor of prolactin secretion.
  • Inhibits the secretion of the anterior pituitary hormone prolactin without affecting normal levels of other pituitary hormones.
  • Has a beneficial effect on clinical symptoms and on glucose tolerance.
  • Restores a normal pattern of LH secretion.
  • Reduces the size and number of nodules of the breasts and alleviates the breast pain often associated with such conditions by normalizing the underlying progesterone/oestrogen imbalance.
  • At the same time it reduces prolactin secretion in patients with elevated levels.
  • Indications: hyperprolactinaemia in men- prolactin- related hypoganadism.
  • Antidepressant properties.

After reading that list tell me if bromo is not one of the greatest ‘unknown’ drugs out there. For almost all of the problems steroids cause, Bromocriptine can help solve them. For example, it inhibits prolactin secretion which could solve the problems of gyno caused by deca and/or tren (though its still debatable if either cause prolactin secretion), does not effect other pituitary hormones, has a beneficial effect on glucose tolerance (some steroids cause insulin resistance), restores normal LH secretion (ala clomid, nolvadex, HCG), reduces size and number of breast nodules (anti-gyno properties [even in already developed nodules]) and alleviates breast pain associated with progesterone/oestrogen imbalances (no more itchy, prickly nipples), treats hyperprolactinaemia, hypogonadism and has antidepressant properties (in some users, steroids cause depression).

Clearly this is a ‘supplement’ all who are ‘on’ should be using.

One last trick up the sleeve

Patients used a hot tub for 30 minutes a day, six days a week, for three weeks. During the three-week period, the patients’ weight decreased by a mean of 1.7-2.7 kg. Their mean fasting plasma glucose level decreased form 182 mg per deciliter to 159 mg per deciliter, and their mean glycosylated hemoglobin levels decreased form 11.3 percent to 10.3 percent. They also reported improved sleep and an increased general sense of well-being. Most likely the benefits resulted from increased blood flow to skeletal muscles.

Hydroxy Elite
someone from Demotte
Total order for 46.94 USD
Liquid Labs T2
someone from South Portland
Total order for 39.98 USD
Basic Cut Stack + 8 items
someone from New Port Richey
Total order for 152.99 USD
someone from NEWARK
Total order for 217.92 USD
someone from Ebensburg
Total order for 149.99 USD