Performance Nutrition

By Lucho Crisalle RD

Over the years, I have found that poor eating habits are the leading reason for failure in attaining optimal health and fitness. The habit of eating a balanced and satisfying meal is very often the missing link in optimal health and fitness. There are many reasons for not following a healthy diet; I have found that a lack of knowledge combined with an abundance of misinformation, tend to be the most common ones. With that in mind, I decided to write this article to “demystify” nutrition, and to educate you, the fitness professional, along with the general public on the topic. I have learned that people learn more easily with the use of analogies. Because everyone is familiar with how automobiles function, I have chosen to use them as the “vehicle” (no pun intended) to make this information even easier to understand.

In view of the fact that we are bombarded with so much nutritional information, it is very hard to decipher whether the source is legitimate or not. All the information in this article was based on clinical studies, along with my many years of experience as a clinical and sports dietitian.

The question I get asked most often is “what and when should I eat?" There is a wealth of contradictory nutritional information available including: eat carbohydrates or don't eat carbohydrates; eat before going to bed, do not eat three hours before bed, or do not eat after 6 p.m.; combine foods, or do not combine foods. It appears that there is no end to this litany; hence, you should ignore the folklore and the hype and get your nutrition information only from a reputable source.

Most of my clients’ goals are to gain or maintain their muscle mass and get rid of some body fat. Although one may think that these are mostly aesthetic concerns, the truth of the matter is that body composition or body fat percentage is a true measure of health as opposed to how much we weigh. We are not concerned with how much you weigh, and neither should you. It may surprise you to know that a pint of water (two cups) weighs a pound; and that you may gain or lose a pound or more of body weight based on your hydration status and daily fluid intake. Thus, your success or progress cannot be based on your body weight. If I were to weigh you, have you drink a pint of water, and then weigh you again, you would be a pound heavier. Will you be fatter? No, you will just be less thirsty, and a pound heavier!

As you begin an exercise program, your body starts to store more "fuel" in your muscle cells. This fuel is called glycogen, which is simply many glucose or blood sugar molecules hooked together and stored in your muscles and body cells for later use.

These glycogen molecules are so highly concentrated that your body must also store water in your cells along with glycogen in a ratio of 1:3 (one molecule of glycogen to three molecules of water). Because water weighs a pound for every pint and glycogen also weighs considerably, your weight is sure to increase as you increase your exercise levels, and your glycogen and water storage increases in response to the increase in exercise.

An analogy helps illustrate this phenomenon quite easily: If your fuel tank is on empty and you are going on a long trip by automobile, you will most likely fill up your tank. However, if your tank is on empty and you are only going to the corner store, you will most likely not go out of your way to fill up your tank. The same is true with your glycogen storage; the more you exercise, the more your body begins to store glycogen and water. Certainly, your car does not weigh as much when it is empty as it does when it is full. Well, does a car "get fat" every time you fill up the tank? Of course not! A car has only one gas tank; in the body, in contrast, there are thousands of cells that fill up with glycogen and water so you can use it as fuel next time you exercise, causing an increase in body weight, but not necessarily in body fat. The only way to know the difference is to track your body fat percentage by measuring it weekly.

When looking at your body composition weekly, we look for the following four signs:

·         A gain in muscle and a loss in fat  = you have a perfectly designed meal plan.

·         A gain in muscle and a gain in fat  = the meal plan includes too many calories.

·         A loss in muscle and a loss in fat = you are eating enough calories, but may not be eating enough protein.

·         A gain in fat and a loss in muscle = you are either not eating enough protein, or not eating enough calories, or both.

This is why it is critical to meet with me weekly for the first month of the program so that a "baseline" on how your metabolism is working and how it reacts to the nutrition and exercise plan introduced can be established.

I help my clients achieve their goals of gaining muscle and losing body fat by teaching them three basic rules of success that are easy to follow no matter where their travels may take them. Before we discuss these rules, let's review some basic nutrition information as well as the mechanism by which fat is stored in our body.

Food consists of three macronutrients (so called not because of their size, but because of the amounts in which we need them), namely, carbohydrates (CHOs), fats, and proteins. Whenever we eat CHOs they first go to the stomach where they are digested, and then proceed to the intestines where they are absorbed into the bloodstream in the form of glucose (blood sugar or blood glucose). As blood glucose levels rise, the body secretes insulin, a hormone that is responsible for storing glucose in muscle and organ cells in the form of glycogen. Normal blood glucose levels are between 80 and 120 mg/dl (a way of measuring glucose concentration or “how thick blood gets”). Whenever blood glucose levels fall below 80mg/dl we feel hungry. If the glucose concentration were to fall well below 80 mg/dl the body would react by slowing down its metabolism to save energy. Continuing with our car analogy, this is very much as if we would let off the accelerator pedal and turn off the air conditioner in our car to conserve energy when we are running low on fuel. Of primary importance to us, however, is the fact that whenever our blood glucose levels rise above 120 mg/dl the residual glucose is stored as fat. Hence the secret to dietary success is to control blood glucose levels throughout the entire day as a means of maintaining a high metabolism and therefore minimizing fat storage. The practice of maintaining normal blood glucose levels alone will have the secondary benefit of helping you avoid food cravings and overeating.

Because blood glucose control is very important in controlling diabetes, many studies have been conducted to determine how different foods affect blood glucose levels. One study is the "gastric emptying time test," which measures how long it takes food to leave the stomach. The reason this is a very important study is that the more quickly carbohydrates leave the stomach, the more quickly blood glucose levels rise. Usually, the more quickly blood glucose levels rise, the more effectively glucose gets stored as fat due to larger insulin secretions, and because of these larger insulin secretions, the more quickly blood glucose levels drop (right after the insulin secretion causes blood glucose to be stored), causing us to get hunger pangs and/or cravings. Gastric emptying time studies show that the longest time that CHOs will stay in the stomach is one hour. In contrast, protein will stay in the stomach two hours, and fats will stay in the stomach three to five hours. This is why you find yourself getting hungry 20 to 40 minutes after having a piece of fruit, or some bread, pasta, rice, veggies, or even some cereal. This is also why you feel stuffed for four hours after having a high fat containing meal. These studies also found that when you combine a protein with a carbohydrate, both the protein and the fat contained in the protein (since most proteins have some fat in them) cause the carbohydrate to stay in the stomach longer (approximately three and a half to four hours), which basically means that this increases gastric emptying time, a good thing, because a longer gastric emptying time also means a slow and controlled increase in blood glucose, which lessens the chances of storing a large portion of this meal as fat due to a quick and high increase in blood glucose followed by a large secretion of insulin. A longer gastric emptying time also means mild successive increases over time, as well as mild or slower successive decreases in blood glucose levels caused by the longer time that it takes for food to leave your       stomach. As a consequence, you do not get hungry as quickly, and are able to do away with your sweet cravings, which are usually caused by the need to raise low blood glucose levels after such a drop as described above occurs.

With this understanding, it makes sense to eat protein every time you eat a carbohydrate. This will increase the gastric emptying time, temper blood glucose swings, and control your appetite/cravings. This raises the question, "what is a protein?" Even today after all those fad protein diets, people are still confused about the difference between a protein and a carbohydrate. It's simple: If it walks, swims, or flies, it is a protein; if it comes from a plant or grows out of the ground, it is a carbohydrate.

Surely vegetarians and other readers must be squirming at this broad generalization. Indeed beans are high in protein, as are many other legumes, plants and even some vegetables. However, in an effort to simplify things and to justify our generalization, we have looked at the largest component of a food, and grouped foods based on this component.

Therefore, even though a 1-cup serving of beans has 15g of protein, it also contains 40g of carbohydrates - beans are therefore deemed a carbohydrate. In an analogous fashion, although an avocado is a fruit, because of its high fat content it is considered a fat. And although milk, yogurt, and buttermilk come from cows' milk, following the same logic, milk, yogurt and buttermilk are all considered carbohydrates even though cows fly……………………………………………..No they don’t! I was just making sure you were paying attention☺.

Given the short gastric emptying time of carbohydrates, no wonder you can be hungry by the time you get to your office after having a bowl of cereal with milk, several pieces of toast with jam or jelly, and a glass of OJ! These are all carbohydrates that leave your stomach quickly and raise your blood glucose levels quickly, which causes an insulin secretion that most likely stores everything you ate for breakfast as fat, and in doing so, causes your blood glucose levels to quickly drop. You then go on without eating until 1 or 2 p.m., further slowing down your metabolism (remember, low blood glucose levels cause your metabolism to put on the brakes), which will most likely cause you to overeat at lunch, or if you are "disciplined enough" and just have a salad for lunch, by the time you have dinner at around 7:30-8:00pm you find that you are ravenous and cannot be satiated no matter what or how much you eat.

But stop! Haven't you heard that you are not supposed to eat after 6:00pm? So, you might as well go to bed hungry. After all, once you fall asleep, you won't need any energy, will you? Actually, yes, you will need energy while you sleep to repair tissues, and conduct all sorts of metabolic functions that take place while you sleep. All these processes require energy. Again, the “no food after 6:00pm” theory is just another fallacy. The truth of the matter is that the human body will do anything to survive; that is its number one priority. Since fat is long-term stored energy, the human body will forego burning fat and will initiate a process called "gluconeogenesis," which simply means "the new formation of glucose." Sounds harmless until you realize that the pathway by which new glucose is formed is by the secretion of cortisol, a hormone responsible for  breaking down muscle tissue and turning it into sugar or glucose so that you can continue to breathe, walk, talk, think, exercise, etc. So even though you think you are not eating, you actually are eating - you are eating your own muscle -slowing down your metabolism, and storing fat. These are most undesirable effects. Because muscle weighs more than fat (muscle takes about two-thirds less room than fat for the same weight), as you eat your muscle you lose weight, so, there is no reason to get all excited about seeing lower numbers on the scale! In the worst case, your body may be entering a downward spiral of continual fat storage and suppressed metabolic rate...hmmm, something to think about.

Based on gastric emptying studies and blood glucose control, we've come up with three basic rules to help you keep your muscle mass and get rid of fat. Rule No. 1 is to eat every three and a half to four hours, whether you are hungry or not. Again reverting to the car analogy, you do not drive your car until you run completely out of fuel and have to call the Automobile Club to rescue you….well, hopefully that doesn’t happen to you too often. The same applies to your body - you do not want to continuously run out of “fuel” and have Snickers® come rescue you either. The strategy is to control your glucose levels throughout the day as to prevent crashing and craving cycles. Rule No. 2 - the most important rule - is to eat protein every time you eat a carbohydrate. Of course, we want the protein to be low in fat. Before getting to the third rule, let's discuss carbohydrate servings. As blood glucose control is the most important aspect of a nutrition and exercise program, and given that carbohydrates are the only macronutrients that really have an effect on blood glucose levels, we must be able to determine in some fashion what an appropriate portion of carbohydrates is. Along with a portion of carbohydrates, we must also define a portion of protein and a portion of fat so that we not only control blood glucose levels but also control caloric intake. Fortunately, the American Diabetes Association, along with the American Dietetic Association (both are abbreviated ADA), have taken care of this task for us.

There was a study conducted that determined how small a carbohydrate dose it would take to raise blood glucose levels a measurable or noticeable amount. It turns out that it took exactly 15g of carbohydrates to do it. Because the word "serving" had already been used by millions of manufacturers of food products, we could not just redefine that word. The ADAs decided to come up with their own terminology and decided to call a 15g serving of carbohydrates an "exchange." Therefore, even though an entire English muffin may be one serving, since it has 31g of carbohydrates it is considered to be two exchanges. So, instead of having a cup of oatmeal every morning, you're actually having two carbohydrate exchanges. You may very well choose oatmeal, bread, cereal, pasta, rice, potatoes, pancakes, muffins, etc., until you reach the prescribed number of 30g of carbohydrates or two exchanges or as many as I have for that particular meal. Keep in mind that when we cook carbohydrates, they usually expand (rice triples in size, pasta, oatmeal, etc double), and meats shrink by approximately 20%. For this reason, we measure all foods after they have been cooked. The one exception to this rule is oatmeal. Because people have so many different ways of making it: soggy and watery, stiff, like cement, etc, we measure oatmeal before it is cooked; therefore, it does not matter how much or how little water is added to it because it will still contain the same amount of carbohydrates.

There truly is a correct number of carbohydrate, protein, and fat exchanges that an individual needs per day, and it is not a one-size-fits-all 40-30-30 or 60-20-20 recommendation. Thus, Rule No. 3 is to become aware of what an exchange is and how many you need per day as well as in what combination. The number of carbohydrate exchanges you will be eating per day depends solely on your weekly cardiovascular and daily living activities - just how active you are. In contrast, the number of protein exchanges that you will be eating per day depends on your body weight as well as the type of exercise routine prescribed for you. Finally, the number of fat exchanges that you will be eating per day will be the equivalent of 15 to 30 percent of your total caloric intake. Such a balanced meal plan will ensure that you attain your goals of gaining or maintaining muscle mass while getting rid of body fat.

For a quick review, here are the three rules and things to consider:

 1.      Eat every three to four hours; hungry or not!

2.      Every time you eat carbohydrates, make sure you eat them with protein.

3.      Find out what an exchange is, and how many you get per meal/day.

4.      Meet with your nutritionist weekly to monitor your progress and make the necessary changes to keep you on track for attaining your goals.

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