DEAR DR. BLONZ: I am requesting your input on an ongoing debate at my office. What is the best type of snack food to eat when under stress; would it be carbohydrates, fats or protein? -- F.L., San Francisco

DEAR F.L.: Reaching for snack foods under stress is not a good idea; a brief primer on how stress affects the body will help make this point. The presence of demanding circumstances, whether they be psychological or physical, can initiate the body’s innate “fight or flight” survival routine that’s hardwired into our biochemistry. Once the stress alarm is activated -- even if there is no actual “physical” threat to be confronted -- the body gets prepared to go to battle or take flight to find a safe location, either of which requires immediate physical activity. One key goal is to increase the blood level of fuels essential for muscular work, and a gearing up of our metabolism to handle all aspects of any fight or flight ahead.

The main hormone is adrenaline (also known as epinephrine), released by the adrenal glands that sit atop the kidney. Adrenaline causes glycogen, a form of glucose stored in the liver, to break down and release glucose into the bloodstream. Glucose is ideal because it’s the only fuel that can power muscular work without any need for extra oxygen. It is the fuel that allows a burst of muscular action to catch a falling object. Fat is our main fuel, but it requires oxygen to release its energy. So, in tandem with the release of fats, adrenaline causes the heart to beat with greater intensity to facilitate blood flow, and cues the lungs to breathe deeper and more rapidly to increase the level of oxygen in the bloodstream. It is important to consider that in an emergency there is an immediate need for extra energy. Waiting for deep breaths to raise the oxygen level in the blood could affect our chances for survival.

From all this, we can see the connection with glucose, carbohydrates and physical stress, but reaching for carbohydrates or any other snack when you are stressed is somewhat iffy. The stresses at your office are more likely to be psychological than physical. These are not situations that require the physical action prepared for by the “fight or flight” response. There won’t be any muscular effort to burn up the glucose that will be dumped into the bloodstream; it will simply go back into the liver and be made back into glycogen. If, however, you had reached for a carbohydrate snack to quench this nonphysical stress, you would further increase your blood glucose level, and the excess would then end up being converted back into fat (most of it being deposited as visceral fat around your waistline).

A better strategy for the surge of stress is to get up, have a glass of water and move around, perhaps go up a flight of stairs, or go out and get some fresh air. This will use up some of that extra glucose and help quench that unneeded element of your “fight or flight.” That’s much better than stewing in your own juices and downing a sugary snack. Afterward, if you feel the need to have something, have a piece of fruit or a glass of fresh fruit juice and be sure to eat slowly. Finally, if stress is a frequent companion to your workday, take some time to participate in an exercise program. The better your level of physical fitness, the easier it is to cope with stress.

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 belong to an eating club, and we are all senior citizens interested in living a long life. Years ago, we had discussed how palm oil is a dietary no-no, but I would like to find out about hearts of palm. I enjoyed them when at a party during the holidays, and I now use them in salads quite frequently. I realize that they are part of the palm and I had mentioned this at the club. We debated the benefits and potential dangers of this at the meeting, and I said that I would find out more. This question is my attempt to provide the needed information. -- S.T., Chicago

DEAR S.T.: I like the concept of your healthful eating club. Hearts of palm come from the palm plant, but not from the oil-containing portion. A one-third cup serving of hearts of palm contains less than a half-gram of fat, 14 calories, 207 mg of sodium, 1.5 mg of iron and 1 gram of dietary fiber together with manganese and smaller amounts of vitamin C, folate and other nutrients. But why do you classify palm oil as a no-no? This undeserved reputation originated from the misplaced branding of palm oil and all other tropical oils as foods to avoid at all cost. These foods can play a minor role in any well-balanced diet.

DEAR DR. BLONZ: I am 81 years old and have been a vegetarian for over 25 years. I was advised by my doctor to go on a diet that is low in sugar and fat. The only sugar I had been eating was from fresh fruit. I purchased some “no sugar” low-fat ice cream. There are three grams of sugar per half cup. The carton reads “sugar alcohol seven grams per half cup.” What is “sugar alcohol,” and is this anything of concern? -- S.M., San Diego, California

DEAR S.M.: The term “alcohol” refers to a particular chemical structure, and while there are many different alcohols in nature, a reference to alcohol in food or drink usually refers to the compound known as “ethyl alcohol.” There is an exception to this, however, and that is the sugar alcohol. This is a family of carbohydrates that contain an “alcohol” structure, but you won’t need an ID to buy them. The sugar alcohols include sorbitol, mannitol and xylitol. They contain fewer calories per gram than other carbohydrates, and they are not absorbed as quickly. As a result, sugar alcohols don’t raise the blood sugar level as rapidly as other sugars, making them useful as a sugar substitute for diabetics and others looking to limit their sugar intake.

Our bodies metabolize sugar alcohols differently than other carbohydrates, and one beneficial aspect of this is they do not feed the acid-producing bacteria that live in our mouth. As such, sugar alcohols do not contribute to tooth decay. They are not considered “sugars” for food labeling purposes and don’t have to be declared on the food label, but they can be listed if desired. The FDA allows food sweetened only with sugar alcohols to be labeled “sugar free.” While they have their benefits, be careful not to overdo it. Sugar alcohols can cause abdominal gas and cramping, especially when consumed on an empty stomach.

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: My question is about chicken meat and fat and the differences between the white and dark meats. I eat a healthy diet but must confess a slight bit of guilt in that when eating chicken, I prefer the taste of dark meat to white meat. I discard the skin and visible fat when cooking chicken thighs and breast pieces, but does dark meat still contain more fat than white? -- B.C., Concord, California

DEAR B.C.: Stored calories in chicken, otherwise known as chicken fat, are under the skin, but some is also deposited around the individual muscle groups. The larger breast muscle doesn’t do much work because chickens are flightless birds. Not so for those leg muscles. There are many different bundles of muscles, each requiring an efficient blood supply and available energy. As domestic chickens tend to hang around and eat all day, they tend to always be in a positive caloric balance. This favors the laying down of body fat, some of which gets stashed in and around the muscles. (The same thing happens to us!) With the working muscles of the legs, there are more opportunities for fat to hide, which explains why dark meat tends to have more fat than white meat.

The “dark” of dark meat doesn’t come from fat; it comes from myoglobin, an oxygen-carrying pigment that is present to a greater degree in working muscles. Breast meat is lighter because it contains lesser amounts of myoglobin. Consistent with this theme, the breast meat of birds that fly, such as duck or goose, is not considered “white meat.”

Go ahead and remove the visible fat as best you can, but even then, there will still be a bit more fat in the dark meat. But you mention that you eat a healthful diet; so why not consider discarding that guilt and simply sticking with the type of meat you enjoy?

DEAR DR. BLONZ: My wife and I love crab. When it is in season, we tend to have a family feast, but afterward, we tend to experience tiredness even into the next day. Is this some sort of coincidence or is there a chemical reason for this? -- C.D., San Diego, California

DEAR C.D.: It’s not likely the crab, at least not by itself. If, however, you tend to have a full plate, and you couple the crab with a high-carbohydrate side dish or a sweet dessert, the combination may be causing a seafood version of the protein-carbohydrate tiredness typically associated with a Thanksgiving feast. The relative amount of the amino acid tryptophan tends to be higher in crab than in other types of protein. When consumed as a part of a big meal that contains carbohydrates, this can give rise to increased production of serotonin in the brain that can contribute to relaxation. It is unclear how this would overflow to the next day unless a leftovers feast continued on the following day, or if the associated toils of the family event had interrupted your normal sleep pattern.

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.