DEAR DR. BLONZ: I am hoping you will weigh in on a discussion regarding eating habits in our house. My concerns relate to my husband's reliance on nutrition bars. The brand he favors contains protein, along with a bunch of vitamins and minerals. Just about every work day, he will have one for breakfast and another for lunch, sometimes with a piece of fruit such as a banana or an apple. Dinners are more normal: We have a variety of dishes, most balanced and healthful, some less so. We often have meat, poultry or fish for dinner.

We are in our mid-40s. My husband takes supplements and works out about three times a week, though his favorite snacks are cookies and chips. He is not overweight and has no health problems.

His reasoning is that the nutrition bars are a reasonable option since he doesn't have the time or energy to make breakfast or bring "real" food to work, and he does not have time to go out to eat. They are also a way to control his overindulgence tendencies during the day so he can give in to his cravings at night. My argument is that he needs more variety, and also he could be harming his colon because of the lack of roughage. There could also be other deficiencies I don't know about. Would you please enlighten us? I have my husband's best interests at heart. -- I.P., Berkeley, California

DEAR I.P.: No question that your husband is doing many good things with his active lifestyle. Nutrition bars have a place, but they are not a balanced, whole meal to be relied on day after day. Those bars are made with recipes designed to accomplish a specific flavor and texture -- and, ultimately, a certain marketing goal. Whole foods, by contrast, provide a working symphony of healthful compounds, honed through millennia of trial-and-error "rough drafts." Everything works together with health and survival as the goal.

We continue to research which components, in what quantity, are best for us in given situations. At present, the whole-food model provided by nature is associated with the best health outcomes for us. Granted, we are not plants, but it seems foolhardy to grab a processed food from column A and another from column B and think we've got it covered. We may feel fine doing so, but chronic disease sneaks up on us like a thief in the night.

A more thoughtful approach is to rely on real, whole foods as the core of the diet. There are many healthful, flavorful alternatives to a daily reliance on nutrition bars, but they require some advance preparation. Suggestions include cereals with fresh fruit for breakfast; lunchtime can include salads or sandwiches with whole-grain breads, sprouts, greens and a rotating menu of stuff in between. Then there is plain yogurt, nuts, seeds, dried fruit and cut-up veggies.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: How does fish farming affect the environment? Also, what are the nutritional differences between fish raised on a farm and those caught in lakes, oceans or bays? -- K.B., Springfield, Illinois

DEAR K.B.: The cultivation and raising of fish and water plants for human use, otherwise known as aquaculture, is a rapidly growing form of agriculture. Studies are generally supportive of the raising of fish in water-based pens.

I say "generally" because these systems attempt to take a natural process and reproduce it in a commercial, fixed-location, semi-enclosed system, and such endeavors never work perfectly. Quality control is crucial as farms cope with the inevitable curveballs that nature throws their way. Adherence to safety standards is essential to ensure that the fish are of good quality before they are harvested and sent to market. When things run well, the fish are safe to eat, consistent in quality, and they look and taste great.

The nutritional value of wild-caught and farmed fish tends to be comparable. One exception might be the amount of the oils in the fish, and the "you are what you eat" doctrine applies. Ocean-dwelling fish such as salmon have a leaner diet composed of smaller fish, insects and sea plants. All these can be sources of the compounds that give salmon meat its flavor and color. Those raised on farms dine on controlled diets. Because the genes of the salmon are responsible for its long-chain omega-3 fat production, these levels tend to be comparable between farmed and wild fish. Farmed fish, however, tend to contain more fat per serving.

Keep in mind that based on where they live and feed, even fish in the wild can accumulate toxic compounds. The controlled environment of the farm-raised fish can translate to lower levels of natural toxicants, and studies have borne this out.

Finally, aquaculture can be effective, but there can be no promise of an unlimited supply of fish. Care must be exercised to respect the area's ecology. Overcrowding can quickly turn the effort into a waterborne version of a factory farm. Depending on the location and breeds being raised, there are risks of escaping fish introducing an unnatural species that could interbreed with, or destroy, other area inhabitants. There are also risks of disease transfer, and the problems related to waste disposal and antibiotic use.

No question, fish farms need to operate in an environmentally friendly manner. We, as consumers, can help the system by patronizing those who do it right. Ask at your local fish market, or supermarket counter, where their fish come from. Identify your issues of concern, and let them know that you care. If are unable to get satisfactory answers, take the issue up with the store's corporate headquarters. Your purchasing power can help affect change.

Check out the Marine Stewardship Council (msc.org), Friend of the Sea (friendofthesea.org) and Cleanfish (cleanfish.com) as examples of organizations seeking to foster sustainable aquaculture. As always, it is best to eat a wide variety of foods. Whether caught in the wild or sustainably raised through aquaculture, fish are an important part of any healthful, varied diet.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: Our daughter has eaten mostly vegetarian throughout her teens. She is not a vegan -- she eats seafood and dairy -- and she has been happy and healthy with her diet. Now comes an ideal opportunity to study in Chile, a country not known for its vegetarian proclivities. She will live and work in a rural area, and will need to conform to the normal dietary patterns of her host family.

Is there a "best" way to reintroduce meats such as chicken, beef and pork into a body that hasn't been exposed to them in years? We are concerned that initially she will be unable to digest this food, and it may leave her feeling quite sick. We'd like her to adjust her diet before she leaves home. Do you have any idea how long we should allow for her system to readjust to meat? Should we supplement her diet with protease enzymes? If so, for how long? Is there any possibility that her genes for producing proteases are permanently turned off?

Our daughter is quite enthusiastic about this opportunity and will do whatever it takes. We've got a few months until she leaves, and are most anxious for her transition to be as comfortable as possible. Any advice you can give us would be most appreciated. -- S.T., Seattle

DEAR S.T.: You need to give the human body a bit more credit. I do not believe that your daughter will have much difficulty making the transition -- at least not from a physiological standpoint. If she has been consuming fish and dairy products, or any food containing protein, she has already been using the relevant digestive "machinery." This includes the acid environment in the stomach and the protein-digesting enzymes needed for meats. There is no basis to believe that enzyme supplements would provide any advantage. She may get exposed to some novel fruits, vegetables, spices and herbs, and caution may be needed with public water in some areas, but it is unlikely that your daughter will have much difficulty digesting the meat in her diet, or that it will make her sick.

Chileans do eat meat, but there is a great variety of foods to sample. The basic Chilean diet focuses on bread, beans, potatoes and meat, but there is a long coastline and fish are plentiful in many cities. There are many soups and stews that combine corn, meat or chicken, and a variety of vegetables. Much will depend on the family your daughter lives with, but it is very likely that they will be interested in helping her feel at home.

Your daughter's attitude seems totally appropriate and on target. You could always slowly reintroduce meat as a condiment, say as a part of a sauce, to help her out. Then, over time, gradually have more meat-centered meals. Have her chew her food thoroughly and drink appropriate fluids. I expect her time in Chile will be a positive and enriching experience that will last a lifetime.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.