Professional Cycling

Nutrition is a very complicated and mysterious science. Not so much because researchers and scientists lack understanding about food and what the body does with it. Actually we know more than ever about the relationship between food and human life with new and exciting discoveries being made every day. What makes nutrition, especially sport nutrition, so interesting is that every “body” responds uniquely to what is put into it.

As athletes, we are all a “sample of one”. Take saturated fat and blood cholesterol for example. There are these recommended blood cholesterol numbers, based on your age and weight that your cholesterol should not exceed for risk of heart disease. And for the vast majority of the population this is safe a prudent advice. But for a small percentage of people, because of their genetic makeup, a cholesterol number that would be alarmingly high most is normal and they suffer no ill effects. This not to say that these folks can eat all the cheeseburgers and french fries they want and ignore their cholesterol numbers, it just means that they do not fall within the statistically average set in the population for cholesterol risk. Such is that case with many other basic nutritional standards.

Another factor adding to the confusion is the almost endless variety of human diets. Every culture has it’s own dietary standards based on geographic and economic limitations and cultural history and a diet that is healthy and beneficial for one race or culture might not necessarily be good for another group. I know this first hand from traveling to races in other parts of the world. For example, after several days racing in Guatemala our boys were starting to feel the effects of the limited diet on their energy levels. To keep the boys from getting sick there were a lot of “native” foods that we could not risk eating. This was not a problem for the South American riders who could eat as much as they wanted at every meal and were never under nourished. For the average traveler, a limited diet is not a problem. But for an elite athlete, used to specific diet and optimal nutritional support this can be a huge problem.

As an athlete, you want the best nutritional advice possible to support your training and competition. If you are thoroughly confused by all the claims and ever-changing array of sports nutrition products, you are not alone. Even the PhD’s have a hard time keeping up. Just like good training advice, good nutritional advice can be really hard to come by.

Nutrition experts change their recommendations as more information and new research shines new light on the mysteries of nutrition and human performance. Adding to the confusion is a media and marketing blitz that abounds with half-baked nutrition claims and advice based on questionable, and oftentimes, bad science. Having good information is the key making sound and informed decisions about your diet and nutritional needs. My best advice is that you investigate on your own and keep it simple. 90 percent of what you may can be found on the shelves at your local grocery store. The remaining 10 percent is available in quality sports nutrition products and vitamin supplements.

Understanding Fats
Since FAT is considered the major villain of the American diet, let’s start there. The message we have been getting over the last 10-15 years is that we should be cutting down on fats in our diet. Government health experts and nutritional researchers recommend that a “maximum” of 30 per cent of our daily calories should come from fat. The national average is closer to 40 percent. This overly simplistic advice has remained consistent for some time, yet it lacks the greater explanation of dietary fat. The reason for advising lower fat intakes has been related to cholesterol. Put simply, studies have found that eating less fat leads to a lowering of blood cholesterol levels, which in turn reduces the risk of heart disease.

However true, this broad based conclusion ignores the relationship between different types of dietary fat and blood cholesterol levels. For starters, there are different types of blood cholesterol, and different types of dietary fat. Total blood cholesterol includes two main sub-types: LDL (low-density lipoprotein) cholesterol and HDL (high-density lipoprotein) cholesterol. LDL is the “bad” cholesterol since can lead to harmful fatty deposits on the walls or your arteries causing restricted blood flow and life threatening cardiovascular stress. In contrast, HDL is a much friendlier form of dietary fat as is thought to help reduce coronary artery disease. The “ratio” of LDL cholesterol to HDL cholesterol is thought to be more relevant than “total” blood cholesterol alone.

Good Fatty Acids vs. Bad Fatty Acids
Fat is a major source of energy in the endurance athletic diet. Fats are also critical components of healthy cell membranes and are necessary for the absorption of fat-soluble vitamins. Fats come in a variety of forms, all of which are present in the American diet. However, some fats are better for you than others.

Saturated fats are the most common. They tend to be solid at room temperature, and are mainly found in animal-derived foods like meat, poultry and processed meat products, as well as milk and dairy products. Vegetable sources of saturated fat are less common but include coconut and palm oil, cocoa butter and chocolate, all very common in the western diet. All forms for saturated fat contribute to increased LDL levels but not all at the same rate. The type of saturated fat in butter, for example, strongly increases LDL levels while beef fat increases LDL levels to a lesser degree and cocoa butter fat increases LDL levels even less.

Mono and Poly-unsaturated fats, mostly found in oil form, tend to be liquid at room temperature, and are mainly derived from vegetable sources. Unsaturated fats are considered healthier for the diet and replace harmful LDL cholesterol with more friendly HDL cholesterol. Oils high in mono and poly unsaturated fats are olive, canola, safflower, sunflower, corn, and soybean. These fatty acids are also found in foods like avocado, olives and margarine made from the aforementioned vegetable oils.

Generally speaking, it is a good idea to minimize saturated fat in your diet. However, fat is an important part of your athletic diet so just cutting fat is not the answer. Substituting mono and poly-unsaturated fats for saturated fats has been found to decrease LDL levels while leaving HDL unchanged. This is in contrast to what happens when saturated fat is eliminated and replaced by carbohydrate only to maintain daily caloric intake. Total blood cholesterol levels will fall but this reduction is the result of lower LDL and HDL combined and not a change in the ratio.

Exercise is good for your HDL cholesterol
The good news is that exercise seems to have a positive effect on blood cholesterol ratios. In particular, aerobic exercise has been shown to boost levels of HDL. Estimates of the increase range from 10-50 per cent. You have to work for this benefit but this should not be a problem for a hard working athlete like you. Experts suggest that an exercise program equivalent to cycling 4-6 hours a week, at moderated levels, over a period of several months is needed have the desired effect on total LDL, HDL numbers. This does not mean that you can ignore saturated fat in your diet but rather that you can maintain healthy levels of dietary fat, from a variety of sources, and let your training help balance the ratio of LDL/HDL blood cholesterol levels.

On the other side of the coin, there is considerable debate about the optimal amount of mono and polyunsaturated fat in the diet. Conventional wisdom puts this figure of around 10 per cent of total dietary calories each day. If you are working on a total calories from fat intake of 15% that leaves 5% of total calories from saturated fat, or about 33% of all fat calories consumed. That seems to be pretty manageable. It also leaves room for reducing total daily calories for weight control by further reducing saturated fat intake. Unfortunately, there is another side to this happy story.

There is growing concern among researchers that high levels of polyunsaturated fats could be linked to increased cancer risk, because high intakes of polyunsaturated fats can lead to more free radical damage at a cellular level. The overall intake of polyunsaturated fats in the population has increased dramatically over the last 20 years. So have cancer rates. With all the research on dietary links to cancer the dietary trends of the last 30-40 years are under heavy scrutiny. At some point researchers will begin to understand the long-term consequences of these established dietary standards on the population. Your best bet is talk to your doctor, minimize the saturated fats and reduce fat intake overall to between 15%-20% of your total dietary calories.
What about Trans Fatty Acids?

Margarines and spreads, designed to be replace butter, are made from mono and poly unsaturated vegetable oils like corn, safflower and canola. Converting these vegetable oils into margarines involves a hardening process, called hydrogenation, which leads to the formation of ‘trans fatty acids’. These fats (which may account for as much as 40 per cent of the fat in some margarines) are now being associated with heart disease because they increase LDL cholesterol and reduce HDL cholesterol. Seems that they may be as bad as the saturated fat they’re supposedly replacing.

With the intense competition in the food industry it is getting easier to buy margarines and spreads that aren’t hardened using the process that leads to trans fatty acid formation. Inspect labels to see which proclaim themselves ‘free of trans fatty acids’.
What about alcohol?

Personally, I don’t know many serious competitive riders who are even moderate drinkers. Not to say that having a beer now and then is a bad thing. In the old days alcohol was thought to be an ergogenic aid. I have heard stories of riders having a “finishing” bottle containing a little brandy, and other unmentionables, to help boost their energy and dull the pain a little during the closing kilometers of a long stage. I suspect that nowadays, with all the attention to doping control that this practice has fallen away with many of the other old traditions.

Alcohol does contain calories, about 7cal/gram, so the energy yield is pretty good. However, your muscles will not store the calories from alcohol as glycogen so they are not the best kind of calories for endurance athletes. The side effects of alcohol consumption are well none, especially the diuretic effect. Dehydration is a serious problem for endurance athletes and the alcohol in beer, for instance, will cause frequent trips to the bathroom and lose of precious fluids. Dehydration is never a good thing so if you have a couple of beers make sure to drink water to balance the fluid lose.

Alcohol consumption is common in the “general population” and there is evidence emerging that suggests a regular “nip” might actually be good for your heart. Apparently this isn’t merely wishful thinking and seems to be backed up by some sound research. Several studies have produced evidence that a small amount of alcohol regularly (1-2 units, a unit is the amount of alcohol in a glass of wine or half a pint of beer) helps reduce stress and lower blood pressure, calms the nerves and promotes relaxation and some of the constituents of red wine seem to have a positive effect on blood cholesterol numbers. This could be good news for the recreational athlete who is a very moderate drinker.

However, it remains that alcohol is associated with a host health problems like liver disease and some types of cancers, mainly due to over consumption. Regular consumption, above moderate levels, will suppress your immune system, making you more vulnerable to viral infections. As an athlete, your best bet is to avoid alcohol altogether during heavy training cycles and competition and keep your intake light to moderate the rest of the time. Be especially careful if you have any chronic health problems like sever allergies or other upper respiratory tract infections.

Fighting free radicals
Free radicals are compounds that occur naturally in the body as a result of aerobic, or oxidative, metabolism. It is theorized that free radicals do damage at a cellular level but breaking down cell membranes and have been implicated in degenerative conditions such as heart disease, cancer and arthritis. They are thought to be involved in the ageing process, attacking the DNA in cell and helping to bring about the general “wear and tear” on the body associated with the getting older.

Your body has several strategies and natural defenses against the suspected damaging effects of free radicals that involve a strong counter attack with substances called antioxidants. The best known antioxidants are household names like Vitamins A, E and C for instance. Some are a bit more obscure, like the mineral selenium, and the enzyme CoQ10. Although your body has these defensive strategies in place naturally they can become run down and less effective with intense training. There is a strong relationship between the antioxidant activity in your body and what you eat and extra antioxidants in your diet can help keep the fight against free radicals going strong.

This being said, do endurance athletes need additional antioxidants to fight off the effects from the high levels of oxidative metabolism? This is a very hotly debated question with very few definitive answers. The vitamin supplement advocates say yes and the unbiased researchers say maybe. As is the case with all supplements you need to look at the cost and potentially harmful effects of taking them. For instance, very high doses of the water-soluble vitamin C have to pass through the kidneys and can lead to urinary tract irritation. Fat soluble vitamins like A, D, E, K are stored in the adipose (fat) tissues and in the liver and excessive intake can lead to harmful toxic levels and harmful side effects including damage to the liver.

The fact remains that there is not hard scientific linking vitamin supplements evidence to improved performance. There may be some evidence linking them to better health when taken in proper doses. As an athlete, you are already consuming larger amounts of healthy food than the average person and thus more vitamins. Some people like to think of taking supplements as “nutritional insurance”. My opinion is that if you want to take vitamins, in safe doses because it makes you feel better about the quality of your diet, go for it.

Free radicals do exist and antioxidants are your body’s first line of defense against them. Additional antioxidant supplementation has not been proven to strengthen your defense against free radicals although the research is ongoing. Some adaptations that result from your training are just as effective. There is research that supports the idea that increased levels of some exercised induced enzymes helps neutralize free radicals. The jury is still out on most of this stuff and without solid scientific evidence the best you can do is follow a balanced training program, eat a balanced diet, take some vitamins if you want and get lots of rest.

Managing your Weight
I never really like to think of putting endurance athletes on a diet. If they need to trim down a bit that can be done over time in a safe a healthy way. My major concern with dieting is the risk of coming up short on the optimal nutritional needs to support training and recovery and maintain health. If you and your coach decide you need to loose some weight, the healthiest way to do it is to cut back a bit on the calories and maintain your current levels of training. Dramatic changes in your program will be hard to stay with and you will likely go back to whatever habits you had that caused the problem in the first place.

For lasting results, that won’t damage your health or performance, aim for a weight loss of no more than 1 lb per week. This is a simple formula since all you need to do is cut 500 calories a day (1 pound of stored body fat = 3500 calories, divided by 7 days = 500/day). The weight will come off slowly and your training continues on schedule. The only rule I have is to not cut calories consumed during training, competition or recovery. You are already on a low fat diet, you may want to look at increasing your aerobic training or reducing your carbohydrate intake. Unused carbohydrate is converted and stored as fat. Otherwise, target the saturated fat in your diet.

The benefits of reaching your optimal race weight and having a lean body are very important to being competitive. Having a power to weight ratio that is safe will help you ride faster and stay healthy. All of this can be achieved with a well managed training program and a consistent and balanced diet. If you need help in any of these areas, ask your coach. If you don’t have a coach, contact Performance Sports and we will help you make good plans.

In Conclusion
Don’t be too surprised as nutrition advice changes from the guidelines currently advocated. As more research is done it is likely that the advice from the experts will change. However, I would encourage you to be skeptical of new claims made by sports nutrition product companies. Their claims are often based more on hype and a need to sell product and not on sound science.

Your personal nutritional strategy should be based on the most current science from a source you can trust and a sensible approach to diet and supplements. Try to include the following into your thinking:

* Minimize saturated fat and trans fatty acid intake
* Keep your total fat intake between 15%-20%
* Use monounsaturated oils where possible instead of those made from polyunsaturates
* Eat plenty of fresh fruit and vegetables. Even canned and frozen will be beneficial
* Try to favor complex carbohydrates over simple sugars
* Keep total carbohydrate intake around 65% of daily calories
* Try to eat foods that have had the least amount of food processing, they are more nutritionally dense and are higher in vitamins and minerals.

This entry was posted on Thursday, October 11th, 2007 at 1:37 pm and is filed under Performance Nutrition. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.