On Nutrition

DEAR DR. BLONZ: How long does it take calories in the foods we have eaten to become body fat? I have a physically demanding job, and I tend to gain weight during holidays when I am less active and tend to overeat. This seems to disappear once I return to work, along with better eating and activity. I am wondering at what point the excess fat becomes "permanent." -- D.M., San Jose, California

DEAR D.M.: Short-term body weight changes can be misleading and should not be assumed to parallel gains or losses in body fat. First, some background: Energy is the most essential commodity of life, and the body conserves and stores as much as it can, as body fat. While essential for survival as a species, this trait has an obvious downside if unchecked.

The calorie, a measure of heat, is the unit we use for the energy value of foods. Carbohydrates and protein provide about four calories per gram, while fats provide nine calories per gram. You mention holidays, so we must mention alcohol, which provides seven calories per gram. (For reference, there are about 14 grams of alcohol in a standard drink: 12 ounces of regular beer or five ounces of wine.) Like other animals, humans are designed to be mobile, so the body turns virtually all excess energy into fat, the most concentrated form.

One of my favorite examples is the plant world, where the priority is growth, not mobility. Plants evolved storing their energy as carbohydrates to get the most growth from their calories, helping them grow fast and spread their leaves to begin collecting energy from the sun. The exception for plants is their seeds, where mobility is again the priority. It explains why we find fat in seeds; this concentrated energy makes them light enough to be carried in the wind or by animals to a new destination with sufficient energy to fuel the growth of the new plant.

Your question is about immediate weight changes. There can be transient fluctuations in body weight due to shifts in body water, which can be affected by what you've been eating and drinking. Then there are unabsorbed materials in the queue for elimination, reflecting meal size and composition. Please enjoy your holidays, and don't fret short-term variances in numbers on the scale. Within a week or so, you'll see if things are there to stay.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 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've been a coffee drinker for most of my adult life, but have now read that coffee absorbs calcium -- that it can even pull calcium out of bones and lead to osteoporosis. Is that true? And if so, does adding milk or half-and-half to coffee provide calcium to counter the effect and keep it from absorbing calcium elsewhere? I have osteopenia. -- S.T., Tulsa, Oklahoma

DEAR S.T.: Osteopenia is a "warning" state where bone mass is less than normal, but not as severe as osteoporosis. Our bones and skeletal system represent a cumulative record of our general and mineral nutrition and lifestyle. This structure can also be affected by genetic predispositions and medications that affect how bones get made and maintained.

Coffee is not a significant risk factor for osteoporosis in those who eat well. Caffeine doesn't actually "absorb" or "pull" the calcium out of the digestive tract or from your bones. Still, excessive intake can have a diuretic (urine-producing) property that can bring about a minor loss of certain nutrients, including calcium and magnesium. Coffee is also an acidic beverage, and it can irritate a sensitive stomach; having food with your coffee tends to buffer this effect.

Higher intake of caffeine coupled with inadequate calcium can be a risky combination. Eating well overall -- including a sufficient intake of dietary calcium -- counters this negative. The goal is a plant-based, whole-foods diet with adequate intakes of essential vitamins and minerals, including calcium. This will have more sway than adding milk or cream to the coffee cup. (One tablespoon of milk or half-and-half will contain only about 15 to 20 milligrams of calcium.)

In an example from the literature, a study in the American Journal of Clinical Nutrition affirmed that women who drink coffee during their postmenopausal years need to pay particular attention to the calcium in their diet. They found a link between an excessive intake of caffeine and an increased rate of bone loss. In this study, "excessive caffeine" was defined as greater than 450 milligrams of caffeine per day. (Note: Caffeine in coffee can vary according to the type of bean and the way it is brewed, but consider an average to be 100 milligrams of caffeine in a 5-ounce cup of drip-brewed coffee.) The study reported that the caffeine/bone-loss effect was not present in women having diets containing at least 800 milligrams of calcium per day.

Aside from caffeine, physical activity also contributes to the health of our bones, which can be said to have a "use it or lose it" aspect. Weight-bearing exercises such as walking, jogging, gymnastics or aerobics can help strengthen the bones -- no matter what age the activities are begun. Other nutrients -- such as magnesium; vitamins A, B6 and D; phosphorous; and fluoride -- are needed for calcium absorption and healthy bones. It's also important to avoid any habitual excess of dietary protein, as this can increase mineral losses.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 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 wanted to tell you how much I enjoyed your column about grilling foods. When I was much younger, I would barbecue two or three times a week using charcoal. That went on for at least 20 years. I attributed that to my developing colon cancer when I was 54. My good friend with a similar lifestyle had the same result. So, with all of that said, you didn't mention specifically the use of charcoal -- any relevance? -- D., via email

DEAR D.: Thanks for your note, and sorry you had to experience colorectal cancer. I am hopeful that you caught it early, as that can make all the difference. We all should undergo routine screenings starting at age 45 or earlier as worked out with our health professionals. The colonoscopy, a critical screening method, is not a joyous experience, but it is trivial compared to the risks generated through avoidance.

The key concern here is the formation of carcinogenic substances when fats drop on a hot surface and get transformed. These nasties can then get carried back and deposited on the food; this can occur with grills that use gas or charcoal, and it can also happen with pan-frying and broiling. When cooking outside, care should be taken to avoid inhaling smoke, especially that from fat flare-ups. When cooking indoors, there should always be good ventilation to avoid any unintended inhalation of these nasty substances, including carbon monoxide, making it important to have a sensor nearby.

Back to your question: Possible contributors were more likely what you were making and how it was typically prepared on the grill. Also involved would be the other foods on the plate and the overall quality of your diet and lifestyle. Then, in addition to those lifestyle and environmental factors, genetic issues can also raise the risk of colorectal cancer; these can be identified by DNA health tests available to consumers.

DEAR DR. BLONZ: Is there a supplement for varicose veins and bad circulation in the legs? Mine ache, itch and feel very heavy whenever I'm standing. -- P.C., Chicago

DEAR P.C.: Rather than thinking first about supplements, your priority should be to determine what is behind the problems with your legs, including that sensation of heaviness that you feel. Check with your physician to discuss these issues. It could involve something as basic as rest or muscle tone, or some other factor for which a supplement would not be of any proven value.

When faced with an unknown, it is best to learn all you can before turning to dietary supplements. This would be especially important if there are other health issues at play and medications being used.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 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.