November 2002

NUTRITION Advice #1  

Good versus bad fats, alcohol, soy, and weight loss 

Liz Applegate, Ph.D (Runners World March 2002)

Eating should be one of life’s greatest pleasures. But these days, with all the late-breaking nutritional news speeding down the information superhighway, it can be difficult for health-conscious runners to take a bite of anything without feeling guilty or worried. 

To help you out, here are answers to four of the most common reader questions I’ve received recently.

Q. I’ve heard that some fats are good for me, while others are bad. Which fats are which?

A. There’s a lot of debate on this.  There’s also a lot of debate on how much fat you need in a healthy diet. A few years ago, all fat was considered bad.  But times have changed (lucky for us), and fat is back “in,” and in certain amounts. Here’s the skinny on fat – the good and the bad.

Omega-3 fat:  that is a good, “essential” fat which means your body can’t make Omega-3 fat on its own.  Therefore, you need to get Omega-3s from your diet.  This important fat helps protect us from age-related ailments such as heart disease, certain cancers, immune disorders, arthritis and possibly multiple sclerosis and Alzheimer’s.  We need just a few grams daily, but most of us don’t take in enough Omega-3 fats.  The best sources are cold-water fish such as salmon, mackerel, and tuna, as well as flaxseed meal and oil (used as a salad dressing, not for cooking). Canola and soybean oil and most nuts also contain small amounts of Omega-3 fat.

Omega-6 fat:  This is another essential (and good) fat.  And we typically have no problem getting enough, since Americans consume plenty of corn oil, sunflower oil, and other vegetable oils. While this type of fat is crucial for healthy skin and proper brain function, too much of it is bad for your heart.  No more than a third of your total daily fat should come from vegetable oils, or about 20 grams or fewer per day.  Consume more than this, and you risk lowering your heart-healthy HDL cholesterol levels.

Monounsaturated fat: This is not an essential fat (your body produces it on its own), but it’s still a good fat.  Studies show that if you take in a majority of your fat from monounsaturated sources, you can lower your cholesterol levels and your risk of heart disease.  So aim to get more than a third of your total fat intake from monounsaturated sources.  Use olive, canola, or peanut oil when cooking, and substitute avocados as a spread or dip instead of margarine, butter or sour cream.

Saturated fat:  This fat has been dubbed “bad” for very good reasons.  Saturated fat increases cholesterol levels and raises heart-disease risk.  Most of us consume too much saturated fat in the form of butter, margarine, fatty meats, full-fat dairy products, and fast food, which is typically prepared with vegetable shortening or lard.  You should limit your intake of saturated fat to fewer that 20 grams a day.

Trans fat:  This fat is formed when vegetable oils are hydrogenated – a process that adds hydrogen to unsaturated fat, making it more solid and increasing its shelf life. Studies show that trans fats are just as bad for your heart as saturated fats.  Cut down on them by avoiding processed foods make with hydrogenated or partially hydrogenated vegetable oils, such as snack crackers, chips, margarine and fast food There’s no set dietary limit for trans fats, but they should be lumped together with your saturated fat budget of 20 grams or fewer a day. 

Manufacturers are required to list total fat, saturated fat, and percent of Daily Value from fat on food labels.  To spot trans fats, you have to scan the ingredient list for hydrogenated vegetable oils.  Soon, label regulations will require trans fat totals.  You won’t find Omegas and monounsaturated fats on labels either, so check ingredient lists for sources of these good fats.



Q. I’ve heard alcohol can be good for you in “moderation.”  What’s so healthy about it, and how do you define moderation?

A. There is considerable research showing that drinking alcohol in moderation, particularly red wine, can boost your health.  The benefits come mostly from substances called flavonoids, which are found in the skins of the grapes.  Flavonoids have been shown to protect arteries from damaging cholesterol.  But even white wine (which doesn’t contain flavonoids), distilled spirits and beer have been linked to health benefits such as an increase in heart-protecting HDL cholesterol levels.  Bottom line:  Compared with teetotalers, those who drink alcohol have a lower risk of heart disease and generally live longer.

But again, the operative work here is “moderation.”  According to the USDA’s Dietary Guidelines for Americans, moderation is defined as no more than one drink per day for women and two or fewer drinks per day for men.  One drink equals: 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits such as gin, vodka or tequila.  By the way, this doesn’t mean you can forego your daily drinks and then have all of them on a Friday night.  That’s not moderation. 

The moderation rule also doesn’t mean you should drink alcohol.  Women, in particular, need to be aware of the downside of alcohol.  Studies show that regular consumption of alcohol (about two or more drinks per day for women and three or more for men) is linked to health problems such as increased breast cancer in women and other cancer types in both sexes, along with a greater risk of stroke, accidental death, and suicide.  Excessive drinking may also compromise bone health and lead to osteoporosis.  So, if you don’t drink now, there’s no reason to start.  If you do drink, be moderate.   

Q. As a runner and vegetarian, I eat soy daily. Is it health to eat this much?

A. Definitely. Soy is a great way to add protein to your diet if you’re a vegetarian, and there are lots of other health benefits associated with soy.  For example, studies show that those who regularly eat soy have a lower risk of heart disease, breast cancer, and prostate cancer. This is because soy contains phytochemicals called isoflavones, which help lower cholesterol levels and block cancer development.  Soy may also be beneficial in protecting bones from mineral loss and osteoporosis. 

But there has been controversy concerning soy, because some researchers believe a very high soy intake may actually boost cancer cell growth. Also, the isoflavones in soy behave like the female hormone estrogen once they enter the body, and there has been some concern that men who eat a lot of soy could experience changes in their testosterone levels.

Recent research has put some of these fears to rest.  Studies have shown that people who eat soy foods on a daily basis do not increase their risk of breast cancer, and the men in these studies have not experienced any changes in their testosterone levels.

However, be cautious about taking isoflavone supplements.  These supplements may cause high levels of circulating isoflavones, which can enhance breast cancer cell growth in women who already have the disease or in those genetically predisposed to it.  Researchers theorize that soy’s benefits come from the interaction of isoflavones with other substances in soy rather that the isoflavones alone.  Therefore, instead of taking isoflavone supplements, you should focus on whole soy foods such as soy burgers, soy mile, and whole soybeans.      

Q. I’ve heard conflicting advice about eating before a run if you’re trying to lose weight.  Should I eat or not?  Is so, what’s best?

A. The evidence overwhelmingly show that eating a meal high in carbohydrates about 2 or 3 hours before a race or workout helps delay fatigue, boosts endurance, and assists sprint performance at the end of a run.  And this is true whether you are trying to lose weight or not. 

To win the weight-loss game, you simply need to take in fewer calories than you expend throughout the day.  Changing the timing of your meals won’t change the number of calories you burn (for running, that’s around 100 calories per mile).

But timing your eating will affect how you feel and perform when you run.  If you don’t take in enough fuel before a run, you may end up feeling sluggish and shaky, which will ultimately compromise the intensity and duration of your run.  The best part about eating something before exercise:  You’ll boost your endurance, add more pep to your step, and ultimately be able to run farther, which burns more calories and speeds weight loss.

So 2 to3 hours before you head out the door, aim for 300 to 500 calories or so depending on your body weight and what your stomach can tolerate. Some great pre-run meals:  pancakes with fresh fruit, a whole-grain bagel with fruit spread, or a sports drink and a low-fat energy bar.  And if you aren’t able to eat in the optimal 2 to3 hour window before your run, down a sports drink, a carbohydrate gel, or an energy bar just before heading out.  You’ll run better because of it.