The Clinic.

Q. Really Low Fat Diet

I am a 27 year old mate and I've been running for about four years. I have completed three marathons and plan to run until my feet fall off. Before I started running I weighed 185 pounds and now I'm down to 160, right where I belong. I consume very little fat in my diet, only about 10 to 15 grams a day. Everyone, including my spinning instructors, friends and personal trainers tell me I need more fat in my diet, but no one can say why

My training schedule includes three to four days a week running, and three to four days a week spinning classes for cross training. I use a heart rate monitor so that my workouts are effective. The way I see it, I maintain my weight with my current diet and level of activity If I were to add more fat to my diet, I would gain weight.

Brian Kantar

Plymouth, MN

A. Most recommendations about fat intake and health suggest that we should get less than 30% of our calories from fat. Some health professionals say that health benefits are best gained at 20%, but there is little support for healthy people to consume extremely low fat diets at 10% to 15%. Assuming that you eat 2,000 calories at 20% fat that should be 400 calories or 45 grains of fat. You state that you eat about 10 to 15 grams of fat a day Your diet is lower in fat than it needs to be to get the health benefits of lowering your risk of chronic disease such as heart disease and some types of cancer.

There are very important benefits to fat in the diet. Many vitamins are soluble only in fat and if your fat intake is low, vitamins A, D, E, and K could be marginal. Also, evidence continues to mount for the benefits of monounsaturated fatty acids. There is evidence that when people go on low-fat, high-carbohydrate diets, total cholesterol levels may decrease, but HDL levels (the good cholesterol) levels do also. A moderate intake of fat, especially monounsaturated fats, seems to lower total cholesterol levels without lowering the HDL levels too.

Your friends and trainers may think you are too lean. You didn't say how tall you are, so I don't know if 160 pounds is an ideal weight for you. If you are truly at a healthy weight, increasing calories from fat just means shifting percentages from carbohydrates and proteins. It doesn't necessarily mean increasing total calories, which could result in weight gain.

Aim for 20% of your total calories from fat to obtain maximum health benefits. Remember that fats provide essential fatty acids and vitamins. I'm sure I don't need to remind you to consider the company fat keeps. Include foods that provide nutrients in addition to fat. Nutritious sources of fat include lean meats, nuts, and low-fat dairy rather than fat from fried foods, snacks and pastries.

Mary Jo Feeney, MS., RD.

Los Altos, CA

A. If your report of 10 to 15 grains of fat per day is accurate, assuming a 2000-calorie daily intake you are consuming only about six percent of total calories in the form of fat, which is extremely low. The importance of fat in a healthy diet is significant. There are important cardio-protective nutrients in certain fatty acids, which are found In flaxseed and cold water fish such as salmon. You may be experiencing evidence of certain deficiencies including dry skin, hair loss, or loss of energy Try keeping a very accurate food diary and analyze it using a good nutrition Web site like www.cyberdiet.com or wwwdietsite.com.

Sarah Harding Laidlaw, MS., R.D., M.P.A.

Glade Park, CO

Q. Tapering Weight Training?

What adjustments should a runner make to his weight training regimen while tapering for or recovering from a marathon? I'm a 39-year-old male, about 5'9" and 150 pounds, with ten years of racing experience. My weekly mileage typically ranges from 45 to 65, the latter during a marathon build-up. It includes a weekly interval session, half miles and miles, with a long run every other week. I use a standard Nautilus workout twice a week on scheduled easy days (one set per machine using enough resistance to reach exhaustion in eight to 12 repetitions).

With the onset of my spring racing season, I tried reducing the weights on the leg machines by about one-third while increasing the number of reps to 20 during the week before a race. The week after, I resumed using full resistance. This approach seemed to work well at first. I had solid personal records in my first four events. By the middle of May however, I was starting to feel a bit overworked, and by Memorial Day I had begun to suffer from a series of minor muscle strains that impaired my training over the summer and limited my performance in the fall. I quit using the leg machines entirely and cut my mileage during the month before the Marine Corps Marathon, but still started the race without much bounce in my legs.

Next year's spring schedule will include Boston and I don't want to make the same mistakes again. When I'm competing what should I do with the weights?

David Kenny

Falls Church, VA

A. From my experience, which includes serving as the strength coach for Steve Spence (Bronze medal winner at the 1991 World Championships in the marathon and 1992 US Olympic Trials marathon winner), you need additional recovery time. Following all major races (and particularly intense training), recovery should include a complete rest from weight training for two to four weeks, in addition to tapering your running. The symptoms of overtraining you have described provide evidence to support increasing your recovery time.

I recommend dividing your training into three different phases--Pre-Season, In-Season, and Post-Season--and adjusting your weight training during each phase. To maximize the benefits of your training, you should vary your weight training to complement your running schedule; include lower body strength training as an integral part of your overall program; give yourself adequate rest and recovery after races or intense training. Racing, especially long distance racing, takes an incredible toll on the body and without enough recovery, performance will suffer. Overtraining can cause major setbacks as you have experienced.

Doug Lentz, C.S.C.S.

Chanbersburg, PA

A. I recommend two to three weeks off weights before a marathon, and possibly the same afterwards depending on your rate of recovery. In between competitions you can use weights but the greatest concentration of weight training comes after the season ends. Resistance work can be used to balance out-of-whack muscles. Include running lots of hills in your resistance work. A hilly training course can simulate the Boston experience. It is a course that can beat up your legs quite a bit.

Priscilla Welch

Tebernash, CO

Q. Running with Diabetes

I have neuropathy in both feet, caused by adult onset diabetes. I am 60 years old and enjoy talking aerobic classes four times a week, as well as some jogging. I have lots of endurance and will often exercise for two hours at a time, but I'm worried that I'll cause the numbness in the bottoms of my feet to get worse. I experience numbness through the balls and heels of my feet. My diabetes is controlled with diet and exercise and I'm not currently on medication. My blood sugars are 100 to 110. I'll appreciate any advice you can provide.

Ron S. Hood

North Reading MA

A. First of all, let me congratulate you on your ability to maintain such tight control of your blood sugar. Having diabetes is very challenging, and you are to be commended for your activity level and being able to control your diabetes with diet and exercise alone.

Neuropathy is not entirely understood; however, it is believed to be associated with a build-up of sorbitol. Sorbitol affects the nerves by causing a lack of sensation and numbness, burning and stinging sensations in the feet, as well as other areas of the body. The fact that you exercise should not increase the neuropathy. The neuropathy is related to the disease state of diabetes alone and should not be affected by the level of your exercise. In fact, the exercise that you do is helping to maintain low blood sugars, which in turn should slow the progression of the neuropathy.

Have your physician or a podiatrist evaluate the pulses in your feet to ensure you have a good vascular supply. If some of these symptoms are related to poor circulation, you need to know. It is also important to make sure that you inspect your feet prior to and after exercising to look for any areas of pressure, redness, or blisters and have those treated promptly. You want to be sure that shoes and socks fit properly and do not cause irritation to your feet.

Jeffrey L. Moore, D.P.M.

Lancaster, OH

Q. Lactate Threshold or Pulse

I read that it is better to determine your training zone based on anaerobic threshold rather than maximum heart rate. I am 37 years old and my MHR is 186. How do I determine my anaerobic threshold heart rate and how do I use it?

Doug Dobrinich

Jupiter, FL

A. I agree that to gain maximum improvement in aerobic activities, it is best to use anaerobic threshold to determine your workout intensity. However, testing is required and anaerobic threshold changes as your fitness level changes. Even with testing, your threshold is linked to your heart rate so that you can monitor your workout intensity during training.

Running at 70% to 80% of your MHR is probably well below your anaerobic threshold. When training near the anaerobic threshold breathing is more rapid and deeper making it hard to carry on a conversation. However, you are still able to maintain this intensity for over five minutes. Once you go over the threshold your training intensity decreases rapidly within two minutes.

You can estimate your anaerobic threshold with the following field test. After a good warm-up, on a day that you are well-rested and well-hydrated, run half-mile or one mile intervals at an increasing intensity (75%, 80%, 85%, 90%, and 95% of maximum heart rate). After each interval you should actively rest five to ten minutes. When you are unable to complete the interval at the percentage listed above, then your predicted anaerobic threshold will be between this interval and the previous one.

Fritz G. Huber, EdD., C.S.C.S.

Tulsa, OK

A. I have found "threshold" intensity is about equal to a pace you could race at for about an hour. Subjectively, threshold pace is "comfortably hard," probably near 90% of maximum heart rate. If you can't breathe with a two-two rhythm (two steps breathing in, two steps breathing out), you are running too fast. Two two should be a comfortable breathing pattern, not a struggle. Threshold pace is definitely slower by 15 to 25 seconds per mile than is your current 5K race pace.

Jack Daniels, Ph.D.

Cortland, NY

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