Dear Doctor: I just heard about a new study saying that whole grains can rev up your metabolism and help you lose weight. Do we need to add tons of whole grains to our diets now?

Dear Reader: We think you're referring to a study published in February in the American Journal of Clinical Nutrition. The researchers did reference a connection between eating whole grains and weight loss, but the original purpose of the study was to examine the role that whole grains play in energy balance and in controlling blood sugar. Let's take a closer look.

In the study, 81 men and women ranging in age from 40 to 65 agreed to eat only the food provided to them by the researchers for eight weeks. They didn't change their activity levels and they gave any uneaten food back to the researchers.

For the first two weeks, during which the caloric requirements of each participant were established, everyone ate exactly the same food. For the next six weeks, everyone had basically the same diet, but with one big difference: The food for half of the participants was prepared with whole grains, whereas the others ate foods made with refined grains.

Throughout the study, participants reported on how full or hungry they felt. In addition, measurements were taken for their blood glucose levels, weight and metabolic rate. At the end of the eight-week study, the resting metabolic rates of the individuals eating whole grains were measurably higher than those who were eating refined carbohydrates.

Researchers noted that the group eating whole grains burned 100 more calories per day than did the group eating refined grain products. That's the same as 10 minutes of high-intensity exercise, or a brisk 30-minute walk. Or, alternatively, it's a tablespoon of peanut butter or a medium-sized banana.

So what are whole grains? Oatmeal or whole-wheat bread comes to mind, but grains constitute a large and varied food group. They include barley, corn, amaranth, buckwheat, oats, rye, quinoa, teff, millet, brown rice and wild rice. (Full disclosure -- amaranth, quinoa and buckwheat are considered to be "pseudo grains," but get included because they offer similar nutritional benefits.)

To be considered as "whole," the cereal grain must contain all of its parts -- the germ, the endosperm and the bran. Collectively, they contain important nutrients like soluble and insoluble fiber, B vitamins, minerals like iron, zinc, magnesium and selenium, and micronutrients. Many breakfast cereals and refined products actually start out as whole grains, but during processing are stripped of most of the nutrient-rich and healthful components.

What does this mean for you?

Although whole grains appear to increase metabolic rate, the degree by which they do so is quite modest. That means the results of the study aren't really an excuse to start eating more. What they do reinforce is a dietary principle we have believed to be true for quite some time -- that choosing whole-grain products over refined foods is better for your body and your health.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I recently read that patients of younger doctors have a lower risk of death than patients of older doctors. How could this be? Don't older doctors have more experience?

Dear Reader: I was fortunate when I started my practice in internal medicine to be surrounded by seasoned, experienced doctors. After I saw patients, the medical questions abounded in my mind. Did I make the right decision about a complicated case? Was this the correct medication for this patient's illness? What lab tests should I order? Should I do an imaging study? I brought my uncertainties to these older doctors, and they gave me sage advice in return.

The study to which you're referring was published recently in the British Medical Journal. The authors analyzed data on Medicare patients over 65 who were hospitalized between Jan. 1, 2011, and Dec. 31, 2014. The physicians caring for them were hospitalists; that is, doctors who care predominantly for hospitalized patients. The authors divided these physicians into four age groups and studied the mortality rates of their patients in the first 30 days after hospital admission. They also assessed the cost of care and whether patients were readmitted after discharge.

The youngest group of physicians had an average age of 35. The oldest group of physicians had an average age of about 64. The study included 10,177 physicians younger than 40, and 1,086 older than 65.

The authors found that physicians younger than 40 had a 30-day patient death rate of 10.8 percent; those over 65 had a 12.1 percent death rate. The greatest disparity was seen among doctors who took care of fewer than 90 patients in the hospital per year; there was no age difference in the death rate among those doctors who took care of more than 201 patients per year.

Neither the 30-days readmission rate nor the cost of care was significantly different between the older and younger doctors.

The authors mentioned that patients seen by the older and younger physicians were the same. However, the oldest group of physicians had slightly more patients with congestive heart failure, lung disease, diabetes, neurologic disorders and mental illness. If you combine the higher mortality rate for all these maladies, that small difference could explain the very slight discrepancy in the death rate seen with the oldest group of doctors.

Also, consider that hospitalist medicine is a relatively new form of practice. The older doctors in the study probably started their careers by working not only in a hospital, but also in an outpatient clinic. The younger doctors in the study may have had more specialization in hospital practice and thus better outcomes in that setting. But the older doctors with busy hospital practices have comparable death rates to the younger doctors, so that potential connection isn't clear-cut.

In any case, this study was conducted among in-hospital physicians, so the findings wouldn't apply to doctors who practice in an outpatient setting.

Overall, I wouldn't make a huge issue regarding a hospital doctor's age unless that doctor sees relatively few patients in the hospital each year. As my older colleagues taught me, experience counts.

Dear Doctor: I've always been a sound sleeper, but in the last few months, I'm tossing and turning way into the night. I really don't want to start take sleeping pills. Is there anything I can do?

Dear Reader: With our busy lives and jam-packed schedules, sleeplessness is becoming a national epidemic. The federal Centers for Disease Control and Prevention say that one in three adults doesn't get enough sleep. In fact, the CDC identifies sleeplessness, also called insomnia, as a public health problem.

The first intervention that we recommend is evaluating for medical reasons for your sudden insomnia. Sleep apnea, depression and restless leg syndrome are a few of the conditions associated with lack of sleep. However, if all is well and you've simply hit a rough patch, here are some steps you can take to give yourself a better shot at a good night's sleep:

Plan ahead: You can help your body to anticipate sleep cycles by following (and abiding by -- that can often be the challenging part) a set bedtime. Decide what time you will get up in the morning and again, follow through.

Get moving: A half-hour or so of exercise during the day can help with sleeplessness. A swim, a brisk walk, getting your heart rate up with hand weights or a game of tennis, whatever is easiest and most enjoyable will work. But don't exercise in the hours before your set bedtime as doing so can actually interfere with sleep.

Here are some more tips:

-- Limit caffeine: If you're a morning coffee drinker, keep it to one cup. After that, skip the caffeine. This includes tea, sodas, energy drinks and (sorry) chocolate.

-- Watch your alcohol and nicotine intake, which are bad for sleep: Both tend to keep you in the lighter stages of sleep, which means waking easily throughout the night. And we wouldn't be doing our jobs if we didn't urge everyone to quit smoking altogether. It's a deadly habit.

-- Make sure to relax: This is easier said than done, which is why we encourage our patients to try mind-body techniques like meditation, mindfulness, breath work, guided imagery, yoga and tai chi. The sustained flow and rhythmic breathing helps to minimize stress.

-- Limit screen time: Many of us are tethered to our phones and computers, but the blue light that screens emit can interfere with sleep. Turn off screens a few hours before bed. And avoid the temptation of sleeping with your phone by your bed.

-- Try a transitional activity: Reading a book, listening to music or doing a crossword can help ease you from daytime alertness to the softer edges of sleep.

-- Create the right environment: Do what you can to minimize light and noise in the bedroom. Earplugs and an eye mask can help. Research shows that we sleep better in cooler temperatures.

-- Try relaxation techniques: Starting at your feet and slowly moving upward, focus your attention on each region of your body. When you feel it relax, move on. If you get to your head and you're still awake, start over.

If insomnia persists, we recommend seeing your physician. He or she can offer new insight and may offer supplements or medications. If needed, your doctor can steer you to a good sleep specialist.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)