I don't recall exactly when "fat" became a four-letter word, but I do know that most people regard fat as though it were as nasty as other words in the four letter category. I often expect some zealous anti-fat believers to talk about fat in hushed tones, the same way people talk about other sinful things. On the other hand, there are those who believe fat has been shamelessly defamed by the scientific and health communities. These fans of fat decry the admonition against eating fatty foods and recommend we eat our fill of all things animal regardless of fat content. Any rational, educated human being would sneer at both camps for their extremism.

In the past year, we have been bombarded with information on diets allowing 10%, 20%, 30% or 40% fat as well some diets allowing unlimited fat. Each diet guru has maligned the others. Not all diets, however, have been armed with scientific research to back up their claims. Most of what we know about the diets higher in fat, comes more from anecdotal evidence than from solid research. Although the anecdotal evidence can be extremely convincing, we should not be tempted to buy into it without some solid evidence. Who among us does not know someone who has slimmed down on one of the popular carbohydrate shunning, protein and fat-loving diets? All hype aside, the question remains: How much fat do we need? Do we need any fat at all? Does it matter where that fat comes from?

Essential Fat

Do we need fat? Yes. How much fat? That answer is not so simple. Some fatty acids (components of fat) are essential. That means our bodies cannot make them so we must rely on dietary sources. Interestingly enough the best sources of these fats are plant foods and fish -- not reduced-fat mayonnaise, polyunsaturated margarine or steak. We can easily get the essential fatty acids our bodies need from fish and plant foods such as whole grains, vegetables and legumes. In the case of fish, the description "fatty fish" is a good thing. I often get people asking me if it is okay to eat salmon because it is such a fatty fish. The answer is yes, salmon is a great choice. Salmon is high in an essential kind of fatty acid, which makes it okay to eat. As with all things - even those that are good for us - moderation is the key. For your clients who prefer to get their beneficial nutrients from pills, remind them plant foods and fish are sources of other healthy substances their pills will not contain. Food is almost always the best place to get what we need.

You may be aware of the great consumer interest in flax seed and flax seed oil. Perhaps not the magic bullet many people believe it to be, flax seed is a good source of a number of fatty acids and may have some potential health benefits. The seeds can be ground and incorporated into cereals and baked goods. The oil can be used for salad dressings. For more information about using flax seeds in the diet, refer to the flax seed Web site (www.flax.com).

Not all fatty acids are created equal. Some are long. Some are short. Some are medium in length. Recently, there has been interest among fitness enthusiasts in using medium-chain triglycerides (MCT) for their supposed benefits. Although there has been some research to substantiate the glycogen sparing effect of MCT, it is certainly not a regimen for the casual exerciser. In addition, there have been reports of side effects including GI upset and diarrhea.

Lately, there has been interest among competitive athletes in the practice of fat loading as a means of increasing endurance. Some investigators have speculated that high carbohydrate diets used to maximize glycogen storage may be the wrong diet for endurance athletes to follow. At present, the peer reviewed published studies have been equivocal with some studies showing improved endurance on higher fat diets and some showing no change. The hypothesis for fat loading is based on the belief that increasing fat in the diet will improve fat utilization during exercise thus sparing glycogen, thereby lengthening the time to exhaustion. Aerobic training and, to some extent, caffeine, already accomplish that. As of now, there is little convincing evidence that a high-fat diet improves endurance. More importantly, this is not a regimen to be followed by a casual exerciser or even a fitness enthusiast who exercises and trains frequently. Whatever competitive edge might result from such a dietary regimen would most certainly be offset by the potential for detrimental health effects if the diet were followed for any length of time.

How much fat

What is the optimal fat intake for a healthy person who exercises for health purposes? There is agreement among health professionals that it is prudent to not exceed 30% of daily calories from fat and to choose foods that contain predominantly unsaturated (e.g., monounsaturated and polyunsaturated) fats. Unsaturated fats are found in almost all foods but are most common in plant foods such as legumes, vegetables and whole grains. In fact, studies show that by just replacing saturated fat in the diet with unsaturated fat, cardiovascular risk factors can be improved even if total fat is not reduced.

High fat restricting diets such as the Ornish diet should not be undertaken without the guidance of a physician and a dietitian. Diets that reduce fat intake to below 15% of fat calories are difficult to plan without the help of a professional to ensure that you are getting the proper nutrients and calories. Because fat is a very concentrated source of energy (e.g., calories), reducing fat and replacing it with other calorie sources such as plant foods will reduce total calorie intake. Fruits, vegetables, grains and legumes that are naturally lower in fat are also bulky foods that tend to fill people up, hence their benefits on weight loss diets. This is often an advantage to people who are exercising to lose weight and increase overall fitness. It can be difficult, however, for an athlete who is training several hours a day to consume adequate calories to fuel exercise if a very low-fat diet is followed. If for health or other reasons, competitive athletes choose to follow a very low-fat diet, they should consult with a dietitian for help in planning meals.

The fat facts

You should encourage your clients to follow low-fat diets (15% to 30% of calories from fat) with most of their fats coming from unsaturated choices that can include fish, chicken, whole grains as well as fruits and vegetables. Foods like avocados, which although high in fat are rich in monounsaturated fat, and small amounts of nuts like almonds and walnuts as well as the oils made from these nuts when used judiciously can be part of a healthy low-fat diet. Vegetable oils such as canola and olive as well as spreads made with these oils can also be used. Lean meats fit into a healthy low-fat diet when used as "condiments" in amounts that complement plant foods served with a meal.

Fat is neither the villain nor the savior. Recommendations for fat, as with other nutrients, will naturally be vague until a complete assessment of the health status, dietary needs and exercise patterns of your client have been completed. It is always best to recommend a range of intakes rather than one specific number. Rather than advising your client to consume 60 grams of fat per day, it would be wise to help the client plan a diet by using the Food Guide Pyramid, keeping in mind the client's calorie needs and suggesting numbers of servings of foods rather than grams of fat.