Introduction
Carbohydrates play a key role in athletic performance – particularly as an energy source. Carbohydrate, in the form of glucose,
does not only fuel active skeletal muscle, but it is also a metabolic fuel for nerve cells and red blood (1). Elite athletes
and exercise physiologists do not solely view carbohydrates as a fuel source, but also study the effects that carbohydrates
have on physique/body composition. Because of advances in nutritional biochemistry, it has been learned that various types
of carbohydrates affect the body differently. Amazingly, some types of carbohydrates are preferentially converted to fat,
raise blood glucose levels to high physiologic levels, and are linked to health problems such as diabetes, obesity, cancer, etc.
(2,3,6,9). Other types of carbohydrates, such as disaccharides and polysaccharides, are not converted to fat easily and are not
considered to be deterrents to good health. Relative to dietary carbohydrate, this article will discuss the differences between
the glycemic index and the glycemic load. Because of its practical application relative to food intake, professionals in the human
performance industry should consider the glycemic load of a food when designing meals, planning recovery nutrition,
and creating specialized diets to enhance body composition.

The Glycemic Index
The glycemic index was developed by researchers from the University of Toronto approximately thirty years ago, and was
primarily used as a tool for diabetics looking to control their blood glucose (blood sugar) levels (7). Today, many other nondiabetic
individuals are also using this index as a way to choose foods to eat for health, weight loss and performance. Relative
to weight loss, several scientific studies have been conducted with the primary intervention being the glycemic index values
of various diets (4,10,11). Specifically, the glycemic index is a numerical ranking of carbohydrate-containing foods based on
their potential to raise blood sugar levels. Carbohydrates that are high on the glycemic index (>70) are quickly digested and
absorbed. These carbohydrates tend to cause a rapid rise in blood glucose and in most cases a quick rise in insulin. Conversely,
carbohydrates that are low on the glycemic index (~55 and below) are more slowly absorbed and subsequently cause
a relatively small increase in blood sugar and insulin. Hence, the glycemic index allows an individual to indirectly estimate
both blood glucose and insulin levels which is not only important for diabetics, but is also important for anyone looking to
control body weight or when determining what type of carbohydrates to ingest prior to and following exercise bouts.

Determining the Glycemic Index of a Food
Researchers measure out a portion of food that contains 50 grams of carbohydrate. For instance, 4 slices of bread, 1 1/4 cups
of rice, 1 1/2 pounds of carrots, and 2 medium apples each contains about 50 grams of available carbohydrate. A food is fed
to a group of test subjects and their blood sugar responses are measured. The test subjects’ blood sugar response to the food
is then compared with their response to eating 50 grams (about 3 tablespoons) of pure glucose. To illustrate this point, oatmeal
will be used as an example. Oatmeal on average is approximately 49 on the glycemic index. When plain oatmeal that
contains 50 grams of carbohydrate is eaten, it will produce an increase in blood sugar approximately 49% of that obtained
when the same amount (i.e. 50 grams) of straight glucose is consumed.

Foods That Have a High Glycemic Index
Generally speaking, foods that rank high on the glycemic index include products made from finely ground flours like bread
and baked goods; processed breakfast cereals (Corn Flakes®); candy (i.e., jelly beans), and baked, mashed, and French fried
potatoes (5). Foods that rank lower on the glycemic index include most vegetables and fruits; sweet potatoes; legumes; minimally
processed whole grains such as thick-cut oatmeal, oat bran, barley, pasta; and dairy products (5).

Glycemic Index vs. Glycemic Load
The glycemic index is not the only tool that can be used to determine the blood glucose response to a particular food item.
The glycemic load uses the glycemic index as well as the actual amount of carbohydrate (i.e. the serving size) to determine
the overall effect that a carbohydrate-containing food has on blood sugar and subsequent insulin values. As mentioned
earlier, the glycemic index compares different food sources that contain carbohydrates of the same quantity (i.e. 50 grams of
glucose is compared to 50 grams of carbohydrate in oatmeal). However, this is not always practical or realistic because many
foods are not consumed in 50 gram (1.76 ounces) portions. The glycemic load is calculated by multiplying the amount of
carbohydrate in a given serving of food by the glycemic index of that same food and then dividing that number by 100.
For example, a boiled potato has a glycemic index of ~101 and a Mars® candy bar has a glycemic index of ~65. However,
the average serving size of a baked potato is about 150 grams (5.3 oz) and contains 17 grams of carbohydrate. Conversely,
a Mars® candy bar serving size is only 60 grams (2.1 oz) but contains 40 grams of carbohydrate. The boiled potato has a
glycemic load of 17, while the Mars bar is 26. Thus, even though the potato has a higher glycemic index, the Mars® candy
bar has a greater effect on blood glucose than the potato even though the size of the Mars® candy bar is less than half that of
the potato. Dr. Jeukendrup, a respected sports nutrition researcher, reports that foods with a glycemic load of > 20 are high,
11-19 are medium, and < 10 are low (8). The following table lists some common foods with their corresponding glycemic
index and glycemic loads.

Conclusion
While both the glycemic index and the glycemic load provide information relative to the impact that carbohydrates have on
the blood sugar and subsequent insulin response, the glycemic load is a more practical scale for reasons mentioned above.
It is also important to realize that both glycemic index and glycemic load only refer to the food eaten alone. When fat or
protein from other foods are added to a meal containing carbohydrates, the total impact of either score goes down. In conclusion,
since carbohydrate intake and its effects on the blood glucose/insulin response are important for the hard training
athlete, one should consider utilizing the glycemic load to assist in making carbohydrate food choices.

References

Bill Campbell, PhD, CSCS

Cortisol is a hormone in a group of steroids commonly referred to as glucocorticoids. Cortisol is a hormone produced by the adrenal gland as a part of your daily hormonal cycle. However, it is also a key hormone involved in the body’s response to stress, both physical and emotional.  Cortisol increases blood sugar levels, increases blood pressure, and suppresses the immune system, which is part of the body’s fight-or-flight response that is essential for survival. Your hypothalamus, via the pituitary gland, directs the adrenal glands to secrete both cortisol and adrenaline.

Does stress affect eating, weight, and where fat is distributed on the body? This is a question that has begged an answer from experts for many years. The body makes cortisol to help us handle stress. When stress goes up, cortisol levels go up. And it's often repeated that obese people have higher cortisol levels than lean people.

Cortisol has widespread actions which help restore homeostasis after stress, including increasing production of glucose from protein to quickly increase the body’s energy during stressful times.

However, cortisol has a two-fold effect on fat. When the stress first occurs, fat is broken down to supply the body with a rapid source of energy. When we experience something stressful, our brains release a substance known as corticotropin-releasing hormone (CRH), which puts the body on alert and sends it into "fight or flight" mode. As the body gears up for battle, the pupils dilate, thinking improves, and the lungs take in more oxygen. But something else happens as well: Our appetite is suppressed, and the digestive system shuts off temporarily. CRH also triggers the release of the hormones adrenaline and cortisol, which help mobilize carbohydrate and fat for quick energy. When the immediate stress is over, the adrenaline dissipates, but the cortisol lingers to help bring the body back into balance. And one of the ways it gets things back to normal is to increase our appetites so we can replace the carbohydrate and fat we should have burned while fleeing or fighting.

Your body assumes you have just physically exerted yourself, for example running from a lion, and need to restock your reserves by eating a lot of carbohydrates or fatty food that can easily be stored as fat. In reality, you are probably still sitting in your car or at your desk, still fuming and stressed out.

This is where the potential second effect of cortisol comes into play.  Experts now believe that the problem for many of us is being in a constant state of stress. Exposure to cortisol over the long term can lead to weight gain, as your appetite and insulin levels are continuously increased.

It is generally suggested that stress-induced cortisol weight is usually gained around the waistline, because fat cells in that area are more sensitive to cortisol. The fat cells in your abdomen are richer in stress hormone receptors, are particularly sensitive to high insulin, and are very effective at storing energy – more so than fat cells you would find in other areas of the body. This is the most dangerous place to gain weight, as it can lead to metabolic syndrome, diabetes, and heart disease.

If we do accept that chronic stress and elevated cortisol may be factors in weight problems, what can you do if you want to reduce cortisol?

First, focus on becoming stress resistant. One of the best things to reduce stress and improve insulin sensitivity, for example, is getting regular exercise. Exercise not only helps promote weight loss by burning calories, but is also beneficial because it helps neutralize stress and its effects, which in turn helps you keep weight off.

Second, practice stress reduction techniques such as meditation, yoga, and breathing exercises. Improving time management can also be essential to reducing stress in one’s hectic lifestyle.

Third, how a person perceives stressful situations is also important. n. Hence, stress makes life difficult, but our reaction to it is important as well.

References

1. Talbot S, Kramer W. The Cortisol Connection. 1st ed. Berkeley, CA: Publishers Group West, 2002.
2. Epel ES, McEwen B, Seeman T, Matthews K, Castellazzo G, Brownell KD, Bell J, Ickovics JR. Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat. Psychosom Med. 2000 Sep-Oct;62(5):623-32.
3. Smart JL, Tolle V, Low MJ. Glucocorticoids exacerbate obesity and insulin resistance in neuron-specific proopiomelanocortin-deficient mice. J Clin Invest.2006 Feb;116(2):495-505. Epub 2006 Jan 26. Erratum in: J Clin Invest. 2006 Mar;116(3):842.
4. Salehi M, Ferenczi A, Zmoff B. Obesity and Cortisol Status. Horm Metab Res 2005;37:193-197.
5. Prezio JA, Carreon G, Clerkin E, Meloni CR, Kyle LH, Canary JJ. Influence of Body Composition on Adrenal Function in Obesity. J Clin Endocrinol Metab 1964;24:481-485.
6. Streeten DH, Stevenson CT, Dalakos TG, Nicholas JJ, Dennick LG, Fellerman H. The diagnosis of hypercortisolism. Biochemical criteria differentiating patients from lean and obese normal subjects and from female on oral contraceptives. J Clin Endocrinol Metab 1969;29:1191-211.
7. Jessop DS, Dallman MF, Flaming D, Lightman SL. Resistance to glucocorticoid feedback in obesity. J Clin Endocrinol Metab 2001;86:4109-4114.
8. Hellman L, Nakada F, Curti J Et al. Cortisol is secreted episodically by normal man. J Clin Endocrinol Metab 1970;30:411-422.
9. Chalew SA, Nagel H, Burt D, Edwards CR. The integrated concentration of cortisone is reduced in obese children. J Pediatr Endocrinal Metab 1997; 10: 287-290.
10. Chalew SA, Lozano RA, Armour KM, Zadik Z, Kowarski AA. Reduction of plasma cortisol levels in childhood obesity. J Pediatr 1991; 119: 778-780.
11. Strain GW, Zumoff B, Kream J, Strain JJ, Levin J, Fukushia D. Sex difference in the influence of obesity on the 24 hr mean plasma concentration of cortisol. Metabolism 1982: 31: 209-212.

Hormones are the most powerful molecules in our bodies, controlling the function, growth reproduction, metabolism, and repair of every cell. Our bodies require optimal hormone levels, just as they require optimal levels of essential vital nutrients: vitamins, fats, amino acids, and minerals.

Hormone levels are generally optimal in our early twenties but begin to decline at a rate of 2% per year after the age of 30. Hormone levels decline because our glands and the parts of our brain that control our glands deteriorate with age. This age-related hormone loss is natural, but it is not adaptive; it is destructive. It is one of the mechanisms of aging.  It is Mother Nature’s way of canceling us out by deterioration and death.

Hormone loss has been shown to contribute to many of the disorders and diseases that we suffer as we age – diabetes, atherosclerosis, high blood pressure, fatigue, loss of muscle strength, osteoporosis, autoimmune diseases, cognitive decline, increased cholesterol levels, loss of libido, depression, and some cancers. Many have additional non-age-related hormone insufficiencies or imbalances due to hypothalamic-pituitary dysfunction, endocrine gland failure, hormone resistance, and metabolic disorders.

Women are more so affected by hormonal disorders because their complex hormonal system is adapted to produce and feed babies; not to optimize their vitality as it is in men. Women lose vital sex hormones in perimenopause and menopause, and they have a much higher incidence of thyroid insufficiency and cortisol insufficiency (fatigue, aches, anxiety, depression, allergies, and autoimmune diseases).

Progesterone, estrogen, and testosterone are three sex hormones whose names are known by women and are extremely important when considering hormone optimization.  There are also further hormone optimization considerations. 

Each day nearly 200 hormones and hormone-like substances course silently through your body, acting as chemical messengers secreted by nine major endocrine glands (adrenals, thyroid, parathyroid, ovaries, hypothalamus, pancreas, thymus, pituitary, pineal) and other organs.  These hormones affect every cell in your body, helping to determine whether you’re hot or cold, hungry or full, calm or stressed, alert or sleepy, and naughty or nice.  Whether you’re asleep or awake, hormones also build bone, regulate your menstrual cycles, and direct myriad other essential functions. 

So keeping your hormones in balance, in an optimized state, is vital for day-to-day good health.

Metabolism is the process by which your body converts what you eat and drink into energy (movement and heat). Metabolism happens in your muscles and organs and the result of it is what we commonly refer to as "burning calories". Metabolism is essentially the speed at which your body's motor is running. During this complex biochemical process, calories in food and beverages are combined with oxygen to release the energy your body needs to function. Even when you're at rest, your body needs energy for all its "hidden" functions, such as breathing, circulating blood, adjusting hormone levels, and growing and repairing cells.

"Basal metabolism" is the metabolic rate or caloric expenditure needed to maintain basal body functions such as your heart beating, breathing, muscle tone, etc. It's how fast your "motor" is running when you're still in a reclined position or sleeping. Basal metabolism accounts for 60-75% of the calories you expend on a daily basis! The number of calories your body uses to carry out these basic functions is known as your basal metabolic rate (BMR) — what you might call metabolism. Several factors determine your individual basal metabolic rate:

• Your body size and composition. The bodies of people who are larger or have more muscle burn up more calories, even at rest.
• Your sex. Men usually have less body fat and more muscle than do women of the same age and weight, burning more calories.
• Your age. As you get older, the amount of muscle tends to decrease and fat accounts for more of your weight, slowing down calorie burning.

In addition to your basal metabolic rate, two other factors determine how many calories your body burns each day:

• Food processing (thermogenesis). Digesting, absorbing, transporting and storing the food you consume also takes calories. This accounts for about 10 percent of the calories used each day. For the most part, your body's energy requirement to process food stays relatively steady and isn't easily changed.
• Physical activity. Physical activity and exercise — such as playing tennis, walking to the store, chasing after the dog and any other movement — account for the rest of the calories your body burns up each day.

It may be tempting to blame your metabolism for weight gain. But because metabolism is a natural process, your body generally balances it to meet your individual needs. That's why if you try so-called starvation diets, your body compensates by slowing down these bodily processes and conserving calories for survival. Only in rare cases do you get excessive weight gain from a medical problem that slows metabolism, such as Cushing's syndrome or having an underactive thyroid gland (hypothyroidism).

A few ways to boost your metabolism:

• Weight train
• Supplement with healthy fats
• Increase your overall daily activity
• Eat the right carbohydrates
• Fluctuate your caloric intake
• Increase your protein intake
• Perform high intensity cardio
• Eat more often
• Eat whole foods
• Drink cold water