DEAR DR. BLONZ: I am shifting to tofu instead of meat, but I want some guidance as to how much it will take to meet my protein requirements. I weigh 105 pounds and am 5 feet tall, and 1,000 calories is about as much as I can consume in a day without gaining weight. I want to have some idea of how much tofu I should have daily. -- R.V., via email

DEAR R.V.: As a general baseline, protein requirements for adults are about 3.6 grams of protein per 10 pounds of body weight -- so, multiply your weight in pounds times 0.36. Those routinely involved with intense physical activity may need twice that amount. The typical American, even if sedentary, tends to consume more than enough protein -- even above the level recommended for active adults.

One serving of meat is approximately 3 ounces, equivalent in size to a pack of playing cards. If trimmed of visible fat, this serving would contain around 25 grams of protein. One cup of extra-firm tofu contains an equivalent amount of protein.

I don’t think it wise for a single food to become the focus of any diet. Consider including vegetarian sources of protein such as nuts, seeds, grains and legumes -- or fish, poultry and dairy, if you are an omnivore. Red meat does not represent a health problem when part of a plant-based, whole-food diet. The issue is not so much its source as its place among the other foods you eat.

Concerning tofu, it is made from soybeans that are soaked, crushed, cooked and filtered. Calcium sulfate is typically added, causing the soy pulp to form a gel. The water is then removed as the soy is pressed into cakes. Tofu has a relatively high content of polyunsaturated fats, a type that can turn rancid when exposed to air -- especially warm air. If fresh, tofu should be kept refrigerated and in water. When you purchase fresh tofu, make sure it has been properly stored. You should take it home in a well-sealed plastic bag that contains water. There are other options, one of which is to buy cakes of tofu in refrigerated, commercially sealed, water-filled packages; another is to buy tofu that is vacuum-sealed in an aseptic carton.

Discard tofu if the storage water becomes cloudy, if a slippery film develops on the surface or if you notice any unusual smells. Also, the tofu should be discarded if it takes on a pinkish tinge -- usually the effect of exposure to air. If the water is changed daily, fresh tofu can last up to two weeks in the refrigerator.

Finally, a bit about your daily calorie comment. Checking the counter at b.link/calcounter reveals that your intake is on the light side for someone of your height and weight. A moderately active adult requires about 15 calories per pound of body weight; if that’s you, it translates to a daily caloric requirement of 1,575 calories. This suggests there might be room on your plate for more food. All these data come from population averages, so keep in mind that the greater your lean body (muscle) mass, the more energy it takes -- even if you are sitting around doing nothing.

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 enjoy eating artichokes, but am skeptical of the claim I read that they can help cleanse the arteries. I would appreciate a comment about this. Also, are artichokes best if eaten raw or steamed? Is the expensive canned version just as healthy? How often should artichokes be eaten, and how much at a time? -- T.T., Walnut Creek, California

DEAR T.T.: This is a good time to be discussing artichokes, as spring is their peak season. The artichoke is in the same family as the sunflower and the thistle. The globe-shaped “vegetable” that we eat is actually the immature bud of a beautiful seven-inch purple flower. That helps explain why springtime, when flowers typically emerge, is when we see artichokes at farmers’ markets. (If you were planning to attend, the annual Artichoke Festival in Monterey, California -- where you can sample anything and everything artichoke -- has been postponed until August.) If left to bloom, the artichoke loses its appeal as a food, but the blossom can serve nicely as a table decoration.

Artichokes are not typically consumed raw, but are eaten after being steamed, boiled or baked, at which point they can be enjoyed hot or cold. Those that come canned are also excellent.

The artichoke is high in vitamin C and fiber, and is a good source of folate and magnesium. The artichoke plant contains several beneficial phytochemicals, some of which are antioxidants and others that may be of help to the liver.

One compound, cynarine, encourages the production of liver bile, which is used to emulsify ingested fats (lipids) during digestion. This plays a role in how we handle dietary cholesterol, but it’s not the same as “artery cleansing” -- no facts to back that claim. Another compound, silymarin, is a mixture of substances also found in milk thistle (an artichoke relative, as mentioned). It has been shown to have liver-protective properties, and the liver makes cholesterol when the body needs it. (Interesting side point: Even if we had no cholesterol in our diet, the liver would make all we needed.)

But it is important to understand that while the part of the artichoke that’s eaten may contain some phytochemicals, most tend to be found in the leaves of the plant. If a website mentions “evidence” to support a claim, be sure to check the source to see what part of the plant was used in the research.

How often should you eat artichokes, you ask? Let your palate be your guide. The artichoke does indeed have healthful attributes, but it is one player in what should be a grand cast of whole-food characters.

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: From the standpoint of nutrition and energy level, is it best to stick with three meals per day, or spread those same foods into smaller meals throughout the day? -- S.T., Dallas, Texas

DEAR T.X.: The overall nutrition status is not significantly different, because the same foods will be eaten. That said, several studies have shown that midmorning and midafternoon meal breaks can enhance work performance -- but the explanation may be more psychological than nutritional.

Interestingly enough, the subjects in those studies who had not eaten a nutritious breakfast showed the greatest improvement. Their typical “coffee and a quick bite” morning meal gave them a jump-start for the day, but only enough dietary energy to last a couple of hours. The caffeine effect was responsible for much of that. For them, having a midmorning break resulted in a needed energy boost.

A complete breakfast, in the studies, included a source of protein, complex carbohydrates and some fat. Those who ate that at one sitting did not report any significant change if they broke that food into two smaller meals. Multiple meals may help break up the tedium of the workday, but the nutrients absorbed by the body are comparable.

Having several meals throughout the day, often dubbed “grazing,” may have potential benefits for dieters. But grazing also has drawbacks, one of which is that it becomes more difficult to keep a handle on total food intake. Besides, when any time can be mealtime, one might be susceptible to errant snacking -- a pitfall of the unsuccessful dieter.

DEAR DR. BLONZ: As a physician, I am always questioning the description of over-the-counter drugs and herbal supplements as nothing more than “harmless placebos” if they do not work as intended.

The American Society of Anesthesiologists and other medical organizations have put out alerts and printed brochures concerning the potentially undesirable effects of these substances, and the ways they can complicate health conditions and affect other medications. When patients do not consider supplements and OTC meds as drugs, they may not mention them when asked about their drug histories. This could be serious: For example, some supplements might affect the way the blood clots, which would be especially risky during surgery. Unfortunately, the FDA and other government agencies probably don’t get much publicity to warn about such things.

Always be upfront with your health care team about all that you take. An essential ally in this is your pharmacist, as they have records of your prescribed medications. If using multiple pharmacists, be sure they are aware of all you are taking. -- R.B., Phoenix, Arizona

DEAR R.B.: Thanks much for your important note. There is no question that OTC drugs, and herbal or other dietary supplements, can raise the risk of health complications, especially during surgery. Patients need to be forthcoming about everything they are taking, and anesthesiologists and surgeons, or their nurses, need to ask the right questions prior to any procedure. In the same way, medical doctors need to inquire about such substances before writing new prescriptions. Pharmacists must also be given this information so that they have the ability to check for interactions. There are online drug-interaction sites, including drugs.com and rxlist.com, where you can enter all the things you are taking or considering, and see whether there are issues to consider.

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.