DEAR DR. BLONZ: I wanted your take on the Alli diet pill, which I understand is based on the prescription drug Xenical. It is a product that prevents you from absorbing fat? What is your opinion about this type of product? -- F.S., Sacramento, California

DEAR F.S.: Alli is the only over-the-counter (OTC) weight-loss product; the fact that it is OTC means it has established safety and efficacy with the Food and Drug Administration (FDA). Consider it another soldier in the battle against obesity. Alli is a half-strength version of the prescription drug Xenical (Orlistat). These drugs work by inhibiting the action of lipase, a key fat-digesting enzyme that breaks apart the fat in the food we eat before absorption. When lipase is inhibited from doing its job, fats remain in your GI tract and are eventually eliminated. With Xenical, approximately 1/3 of the fat consumed is not absorbed; with Alli, the OTC version, only 1/4 of dietary fat is affected. There is no evidence that either will have any significant effect on calories from carbohydrates or proteins. A side-effect of unabsorbed fats is that they continue all the way though, and that can mean undesirable consequences. Something that allows fat to pass through undigested can also affect fat-soluble vitamins and certain medications, so be sure to check with your physician to see if there are specific cautions for you to consider.

I am not a fan of such drugs as a primary effort against obesity, but I recognize that they might be appropriate as part of a multifaceted effort. For anyone considering Alli, I encourage you to read all the information before you start. Once you purchase an Alli starter pack, you can access a free online counseling service at myalli.com and receive a personalized action plan and answers to your questions. More about this and other diet drugs at tinyurl.com/yb2gndyv.

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DEAR DR. BLONZ: I needed to reduce sodium, which I have done. For seasoning, I use various salt substitutes, but I have found it to be a bit of a zoo out there with many products containing various herbs, while others have potassium chloride to provide pseudo-saltiness of a sort. I would like to know whether any of the ingredients or the potassium chloride are harmful. -- H.T., Dallas, Texas

DEAR H.T.: As you have discovered, there are different takes on the concept of the “salt substitute.” Some rely on herbs and spices, and they should be thought of as “salt-free seasoning blends.” Others rely on potassium chloride, which provides a salty, but slightly bitter, taste that many characterize as metallic. There are formulations designed to eliminate the bad taste. But there is no standard formulation, the only shared trait being the absence or very low level of sodium. This leaves it up to you, the consumer, to sample and find which one works with which dishes. You may be able to get product samples by contacting manufacturers. Also, consider checking among the many low-sodium cookbooks to provide additional guidance. I am not aware of any general safety issues with the herbal components of the seasoning blends.

The potassium-based salt substitutes should not represent a health risk when used sparingly. They should, however, be used with caution by anyone with kidney or other health problems that involve the way the body handles potassium. Ask your health professional if you have questions. Those taking diuretics or medications that prevent potassium from being eliminated through the urine should also speak with their physician before they use this type of product.

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 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.