It is true that restaurants' health food offerings have a difficult time competing with burgers and fries ["Hold the Health, Serve That Burger," front page, Aug. 18], but a big part of the problem is that what restaurants consider to be health food and what are important elements in a healthy diet are different things.

For whom, exactly, is a Blueberry D'Lite yogurt parfait considered healthful?

And the misconception that "low fat" means healthful excludes a range of healthy, calorie-rich foods that are high in monounsaturated and polyunsaturated fats such as nuts, whole grains, fish, vegetable and olive oils, and avocado. Too many restaurant salads are bowls of iceberg lettuce -- an abomination -- devoid of vegetables and oils to provide flavor.

Restaurants would do everyone a favor by simply offering their normal menu items in smaller portions. A good, lean hamburger can be a wonderful entree, and it is even better when it does not fill the entire plate or require a cavernous mouth. Dads will buy these items, and kids will eat these items. Most important to restaurants, customers will want these items.

THOMAS G. SHERMAN

Washington

The writer is a professor in the Department of Physiology and Biophysics at Georgetown University.