DEAR DR. BLONZ: What is the comparison between the vitamin, mineral and lycopene content of sun-dried tomatoes versus cooked and fresh tomatoes? -- F.F., San Jose, California

DEAR F.F.: Sun-drying will reduce vitamins C and A, and, to a lesser degree, some of the other vitamins, but the mineral content is comparable. As for lycopene -- a reddish phytochemical that contributes to the tomato's characteristic color -- there isn't any significant difference between the levels in cooked, fresh or dried tomatoes. Lycopene is chemically bound inside the plant-cell matrix of the tomato. The cooking process breaks apart the intact cells and actually makes the lycopene more bioavailable, which means it gets absorbed with greater efficiency.

Sun-drying isn't the same as cooking. In the drying process, the cells shrivel and break as the water is removed, especially if heat is used. If lycopene absorption is your only consideration, the bioavailability of the lycopene will be greater with sun-dried than with fresh tomatoes.

Eating sun-dried tomatoes requires a bit of a chew; this not only helps release the flavors, but it helps mix the nutrients in the meal to facilitate absorption. All the better if there is a little olive oil (or any other oil) in the meal: Lycopene, like other carotenoids, is fat-soluble, so oil present at the same meal will help with absorption. And any lycopene that does not get absorbed still helps our bodies by contributing to the healthful environment in our intestines.

But we miss the point of healthful eating when we get overly focused on the individual substances in the whole foods we eat. The point is that you should enjoy healthful foods like tomatoes in whatever form you like best.

DEAR DR. BLONZ: Please tell me what is so bad about bananas. I have seen online ads saying things like "The 5 Foods to Avoid," and they always show a banana. I clicked on one of these and listened to a long spiel that never mentioned bananas, but had a pitch for a "bargain" $49 offer. I start my day with a banana. Most of my mother-in-law's diet was bananas. I had a dietitian once who didn't want to allow me bananas at all, but reluctantly let me cut one in half! I'm puzzled. -- R.P.

DEAR R.P.: What's bad about bananas? Perhaps bad PR, in that their commodity group does not pursue those who characterize the banana as less than "appealing" (pun intended). There is no science (or logic) behind the banana being touted as a poster child for "foods to avoid." One rare exception might be a person taking medication to control their potassium levels. Concern about the sweet taste in a ripe banana is also misplaced; it is the sugar added to processed foods that should be our concern, not that which is naturally present in a healthful whole food.

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: I find that even with 30 to 60 minutes of strenuous activity a day, I have trouble keeping my weight where I want it. I recently lost 20 pounds and now weigh 125 pounds, but if I were to eat the amount of food needed to supply all the Recommended Daily Allowances, which I assume are required for optimal health, that weight would come back. I also know that recent research shows that restricted caloric intake may actually improve health and extend life expectancy. So this is my question: Is it healthier to be slightly undernourished (not starving) as I am, or to be properly nourished (according to Food and Drug Administration guidelines) but somewhat overweight? -- F.S., Hayward, California

DEAR F.S.: My thoughts are that it is better to be well-nourished (along with being active) and slightly overweight. But I want to point out that the research you mention about caloric restriction and extended life expectancy does not involve any nutritional deficits. Your question needs to be reframed: Undernourishment or being overweight should not be embraced as your only options. Meeting the RDAs need not be a burdensome task.

Those who have been successful at losing weight have experienced the annoying tendency to regain at the slightest provocation. Just looking at food seems to make the numbers on the scale go up. With weight loss, you need to maintain your activity level and stick to a conservative eating pattern to, in effect, establish a new status quo. According to the Calorie Control Calculator (tinyurl.com/pozleth), a moderately active woman weighing 125 pounds needs approximately 1,900 calories per day. There should be no problem meeting your nutrient goals within that allotment.

Eating is one of life's great pleasures, and it makes no sense to get frantic about occasional nutrient lapses. The "R" in RDA stands for "recommended," not "mandatory." If you happen to fall short of your RDA every now and then, your body is not going to degenerate into a slab of broken bones or a mass of oxidized flesh. Just as it does with calories during a diet, the body becomes more efficient at nutrient conservation during times of disease, famine or nutrient inadequacy.

Know the good foods that your body needs, and keep your nutritional house in order as best you can. Healthful eating involves a plant-based diet that is rich in fruits and has plenty of greens and other vegetables, legumes, whole grains, nuts, seeds and dairy products, and an occasional meal with low-fat meat products. I have written an aisle-by-aisle guide of the best choices at the market, and it is online at no charge (goo.gl/ZDHHs5).

A helpful strategy is to have some nutrient-rich power foods in your diet. For example, a vitamin/mineral-fortified whole-grain cereal is a great way to start the day. You can opt for some blended vegetable juice instead of a diet soda, and some fresh fruit and nuts instead of chips. A cup of yogurt provides a calcium boost. Have a green salad with carrots and other fresh vegetables with one of your daily meals. For those on a weight-loss regimen in which fewer foods are eaten, or if there are special needs, it is reasonable to take a dietary supplement to help bolster the intake of certain nutrients, such as calcium and vitamin D.

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: More and more people that I talk with about cancer have been losing faith in the medical community to come up with answers. Their thoughts are that there may, in fact, be cures for cancer; however, having a cure would put so many pharmaceutical companies and medical practitioners out of work that the cures, if they exist, will never be properly researched, publicized or made available. Millions in donations get raised to combat various cancers and other diseases, but where are the results? Not one advancement in finding a cure? Come on! It makes one want to turn to alternatives, as they, at least, promise success. -- T.S., San Jose, California

DEAR T.S.: Why does science take so long to come up with its cures? Frustration leads to a tendency to believe the worst about the medical/pharmaceutical communities. This approach is all too easy to embrace by those who suffer.

We have made amazing progress along many fronts, despite the fact that sophisticated medical research has not been around for very long. Our understanding of the variety of mechanisms of the various types of cancer has grown dramatically. We are poised for great advances on the treatment side -- ones that can take into account the genetic characteristics of the disease as well as the genes of the individual who has had the misfortune to develop it.

It takes enormous amounts of money to do this research, and there is less and less coming from federal funding. We might think that our government has a moral responsibility to fund such research, but our representatives seem loath to enact higher taxes to make it happen. This shifts the burden, or perhaps opportunity, to corporate laboratories, but these are profit-making institutions that have to answer to their stockholders.

It is not ideal, but there is no logic to jumping from this situation to one in which you embrace remedies with no testing or scientific foundation. All they have is a sales-pitch preceded by a condemnation of the status quo.

The ideal physician or researcher is noble in motivation -- at least, most start out that way. It is wrong to think that someone with a handle on a cure would not follow through to find out whether it is valid. Every scientist I know would relish the chance to be on a team that helped end a dreaded disease.

I do appreciate your need to vent. For my part, I promise to remain vigilant in my readings. I've been in the scientific field for a while, and if I believed there was something out there that was being silenced inappropriately, I'd raise my voice to a scream. In the meantime, I will continue to take issue with situations in which personal tragedy and frustration degenerate into a financial opportunity to push questionable remedies on desperate people.

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.