I am a 35-year-old woman who exercises a few times a week, but I find that I always gain weight in winter. Is there any way to avoid extra kilos when the temperature drops? - Y.K., Karmiel Olga Raz, chief clinical dietitian at Tel Aviv Sourasky Medical Center, replies: There are numerous behavioral and physiological reasons for gaining weight during the winter months. Obviously, you spend more time at home because it gets dark early and because of the cold weather. You are less active, go out less and sit more opposite the TV set or computer monitor. So what is left to do? You eat - at the table, opposite the TV or computer, in bed... everywhere. In winter, we cover ourselves up with layers of sweaters and coats and don't see what shape our body's in. We add kilos and don't really discover them until spring. We also eat heavier foods, such as roast beef with potatoes, cholent, rich soups and other high-calorie dishes. We also drink warm beverages such as coffee and tea, and what goes better with them than a piece of cake or some cookies? There are also the physiological and even mental changes. In winter, people's moods tend to change due to the reduction in light. It isn't as dramatic here as in Scandinavia, but it still occurs. The cause is the reduction in the neurotransmitter serotonin due to fewer hours of sunlight. As people tend to suffer from bouts of depression, they may also compensate by eating sweets, which also makes people gain weight. You can't stop the winter, but you can fight it. Use light bulbs of 100 watts or more; it will improve your mood. Prepare meals with complex carbohydrates, such as full-grain rice or pasta and lentils, which are not heavy or high caloried. Add plenty of vegetables. Eat tasty sandwiches with a variety of low-calorie spreads - as a complete meal. You can also toast them to feel warmer. Even cholent can be prepared with fewer calories when you use chicken without the skin rather than fatty meat, white beans, a bit of pearl barley and no potatoes. One can also make warm vegetable dishes such as shakshouka, vegetable quiches with low-calorie cheeses and vegetable soups. I recommend eating every three or four hours to stabilize the serotonin level and get a feeling of calm and fullness. It is also good to get out and walk, as for much of the time, Israeli weather in this season is not too cold and not rainy. From time to time, try on your spring clothes, especially trousers, to get an idea of how your body looks and if you can still fit into them. All of this will help prevent a weight increase in winter. You may possibly even lose weight. I am 50 and healthy. I own a cellphone but use it to a very limited degree for calls. I do, however, use it as an alarm clock five days a week, meaning that it's turned on and close to my head when I'm sleeping. I also keep my cellphone near me at work, on my desk, so that I can answer it promptly. As a result, the cellphone is turned on and nearby almost 24 hours a day - but most of the time it is not used for direct speaking. How dangerous is this? - L.Y., Jerusalem Prof. (emeritus) Elihu Richter, a senior epidemiologist (who does not own a cellular phone) at the Braun Hebrew University-Hadassah School of Public Health and Community Medicine, replies: Several studies show that holding a cellphone next to your head increases risks for certain brain tumors and parotid gland tumors on the side of use, and the risk increases with increasing years of use. Furthermore, studies reported as "negative" report the same associations. In principle, distance from source of exposure is highly protective, since field strength of the non-ionizing radiation falls with the square of the distance from the source. I would guess that positioning the phone at arm's length or more from your head should be highly protective, and, as for wake-up calls, there is nothing wrong with using an old-fashioned alarm clock - also at arm's length because it too generates a field of low-frequency electricity. Keep in mind that field strength from the near field (the cellphone) is more intense in regions located far away from cellphone masts and towers, exposures from which are now the subject of intense research interest. My own observation is that we Israelis do not lack for cellphones, but ears. If we "action junkies" learn to listen more, we will need to talk and phone less. Editor's note: Many cellphones offer the option of the alarm while the phone is switched off. Rx for Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx for Readers, The Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or e-mail it to jsiegel@jpost.com, giving your initials, age and residence.