Why did TV’s “Biggest Losers” have trouble keeping the weight off?

DEAR DOCTOR K: I heard about a recent study that explained why the "Biggest Losers" had trouble keeping the weight off. Can you explain?

DEAR READER: You're likely referring to a study done at the National Institutes of Health (NIH). As many readers will recall, NBC television put on a competition reality show for several years, beginning in late 2004. Extremely overweight people competed to see who could lose the most weight, through diet and exercise, over 30 weeks.

What is biofeedback?

DEAR DOCTOR K: Sometimes you recommend biofeedback as treatment. What exactly is it? What is it like to go through it?

DEAR READER: Biofeedback is a technique that helps you monitor and control how your body responds to external stimuli. By learning to control certain functions, you can improve your medical condition, relieve chronic pain, reduce stress, or improve your physical or mental performance.

Are ADHD medications safe and effective?

DEAR DOCTOR K: My daughter has ADHD. I have heard conflicting reports about ADHD medication for kids. Please tell me, is it safe and does it work?

DEAR READER: ADHD stands for "attention deficit hyperactivity disorder." Children with ADHD have trouble paying attention and are impulsive and hyperactive. These symptoms can get in their way and make it harder for them to function at school and at home. ADHD also interferes with a child's ability to form and keep friendships.

Should I be worried about side effects from long-term use of SSRIs?

DEAR DOCTOR K: I'm nearing 60, and I've been on SSRI medicines for nearly 30 years, for depression. They work for me, but should I be worried about side effects from using them for so long?

DEAR READER: You've asked an important question -- one that should be asked of any medicine used for many months or years. All medicines can have side effects, and SSRIs are no exception. And some medicines can have side effects that become apparent only after long-term use.

Can exposing babies to common food allergens help prevent food allergies later on?

DEAR DOCTOR K: In a recent column you said that parents should give babies peanut products to help prevent peanut allergies. Does the new advice also apply to other common food allergens, like eggs or cow's milk?

DEAR READER: To answer your question I turned to my colleague Dr. Claire McCarthy, a primary care pediatrician at Boston Children's Hospital. For decades, the standard advice recommended by allergy specialists was to hold off on giving babies foods that commonly cause allergic reactions. Parents were advised not to give egg, dairy, seafood or wheat in their child's first year. And parents were told to wait until two or three years to give peanuts or other nut products. It turns out that was bad advice.

What is a POLST form?

DEAR DOCTOR K: My husband has terminal cancer. He has already signed a do-not-resuscitate order. His doctor recently suggested that he also complete a new form called a "POLST." Can you explain what this is?

DEAR READER: As you know (but other readers might not), a Durable Do Not Resuscitate Order (DDNR) lets your husband's medical team know that he does not want CPR if his heart stops beating or he stops breathing. It's usually for people who are near the end of their lives or have an illness that won't improve. It takes the burden of decision-making off family members.

I have chronic pain that interferes with my sleep. What can I do?

DEAR DOCTOR K: I have chronic pain from arthritis. Lately it's so bad that I can't get a good night's sleep. What can I do?

DEAR READER: Chronic pain and insomnia are, unfortunately, a common combination. What's more, chronic pain puts you in double jeopardy: First the pain robs you of restful sleep, then losing restorative sleep makes you more fatigued, which makes you more sensitive to pain.

Do shift workers have an increased risk for health problems

DEAR DOCTOR K: I'm a nurse, and I can be assigned to work the day shift, evening shift or night shift. I hear that shift workers can develop health problems. What is known about that?

DEAR READER: More than 9 million people in the United States are shift workers like you. Studies show that nearly 10 percent of night-shift workers have severe reactions to that schedule. Some become overwhelmingly sleepy during the night shift, when they need to be alert. Some have trouble concentrating and focusing on a task. Others can't really fall deeply asleep during the day, when they need to get some sleep.