Diets of all types work mainly by limiting choice. Whether it’s the Twinkie diet, (whose popularity was unable to prevent the bankruptcy filing of Twinkies manufacturer, Hostess) the Dukan diet, or something in the cleanse category, when your choices are limited, you eat less.

The Atkins diet, arguably the most famous of the choice-limiting diets, probably works in just this manner, according to a 2003 New England Journal of Medicine study. Participants ate fewer calories even when offered unlimited intake of protein or fat, but no carbohydrate.

Put another way, we’re omnivores, pure and simple. And our survival is so tightly linked to this dietary strategy (read: “eat anything edible”) that we simply can’t adapt to a diet that removes one whole food group like carbs.

The danger arises when we go off our “diet” and back to our old omnivore ways. Let’s face it: 4 million years of evolution is hard to overcome. So almost all studies show that diet participants gain weight back over time.

In short, no diet in the last 30 years has been able to stem the tide of the obesity tsunami. Play the CDC’s map of weight progression across the country from 1985 to the present — it’s a pretty sobering graphic. In fact, in 1985, obesity was a small enough problem that half the US states didn’t even bother to keep statistics.

And now that tide is sweeping the globe. Citizens of all major industrialized nations, whether in North America, Europe, or China (yes, China) are getting fat. And no one really knows why. Like most public health problems, it’s likely a complex interplay of factors: less physical activity, more meals away from home that are higher in calories, and easier to digest (and thus less filling) processed foods.

In summary, diets produce short-term weight loss, but little long-term benefit. Shift the focus from “diet” to “healthier living,” and you have a strategy guaranteed to pay dividends regardless of your weight. Best of all, compared to dieting there are far fewer rules to follow.

1. Eat in the moment. We’re constantly admonished to live in the moment, but these days everyone seems to treat eating as a chore not deserving of our full attention. People eat and read, eat and drive, eat and work on their electronic devices — everything but enjoy the food. And if your mind is not engaged in the act of eating, you’ll eat more. (Who has not plowed through an entire bucket of popcorn at a good movie, and wondered where it all went?)

2. Eat a balanced diet. Don’t eliminate food groups, other than garbage foods like processed snacks (chips, pretzels, french fries), sweetened sodas, and processed meats (salami and the like). All these listed items were associated with long-term weight gain in a recent New England Journal of Medicine study. In general, a slightly protein-predominant diet has been shown to be more effective in producing weight loss (think eggs with sauteed vegetables instead of oatmeal with skim milk).

3. Follow your instincts. Don’t want to eat breakfast if you’re not hungry? Not the end of the world, despite what all the guide books say. Use your own knowledge of your strengths and weaknesses to craft your own plan. Are you more likely to lose control at night? Avoid the kitchen after dinner. Too many unhealthy snacks at work? Bring your own stash of dry-roasted unsalted almonds, brown rice cakes, vegetable sticks, or fruit.

4. Eat foods in their most unprocessed form. For example, whole nuts rather than nut butters, fruit instead of juices, and whole grains rather than processed flours.

Lastly, remember that eating should be fun. Don’t make it a chore — that’s what mowing the lawn is for.

Evolutionary biology does not make things easy for us. Our caloric engines were fine-tuned millennia ago, when fuel was scarce and daily expenditures were high. Nowadays, we would benefit from much more wasteful motors — we’re awash in food. Still, it beats chasing wildebeest all day long.

As a result of all this biological programming, many people discover they do not lose weight when they start to exercise. So focus instead on the life-prolonging benefits (which confer to everyone, fat or thin). In fact, I counsel patients that I would far rather have an overweight exerciser than a non-exerciser of normal weight.

Most studies show exercise reduces risk of cardiovascular events (heart attack) by up to 50%. This exceeds the benefits of statins (like lipitor or crestor), and at a fraction of the cost. Recent studies show that these same cardiovascular gains are obtained even with modest investments of exercise.

And don’t forget that physical activity is also proven to improve one’s sleep, moods, and sex life.

No time to exercise? Frequent injuries? Travel interrupts your schedule? Here are five tricks to get you started.

1. Use gravity to your advantage. We typically have nothing nice to say about poor old gravity. It makes our skin sag, our roofs leak and causes our cellphones to occasionally end up in the toilet. But start thinking about exercise in a vertical rather than linear fashion and you’ve got a quick workout in the comfort of your own office or home (try walking the stairs, jumping rope, doing squats, or even standing). There’s increasing evidence that low-intensity, intermittent activity (like standing instead of sitting at work, or sitting on a therapy ball instead of in a chair) is as important as exercise in preventing cardiovascular disease, diabetes, and obesity.

2. Don’t try and imitate Lance Armstrong. He’s a pro, after all. You’re far more likely to get injured or burn out with this strategy. Instead, make your workouts ridiculously simple and short, so they’re almost impossible to skip.

3. And speaking of skipping, don’t skip days. Why not? You’ll inevitably fall off the wagon. Think back to when you learned one of your most-ingrained habits, say, brushing your teeth. Did your parents tell you to brush five minutes three times per week? Of course not. They told you to do it two minutes every day — same weekly duration, but more reliable. Your exercise program must be every day too: rain or shine, warm or cold, light or dark, busy or idle, or you’ll end up with tooth decay.

4. Find a buddy. I know that’s as original as a side of cranberries this time of year, but it really works. If the buddy is a friend, your workout can even double as a social engagement. And in these busy times, who can turn down an opportunity to multi-task?

5. Lastly, a word of advice cribbed from one of my cardiologist professors in medical school: Walk your dog, even if you don’t have one.

I’d been trying to get myself and her to the top of an inflatable slide at the pool, thinking it would be great fun to shoot down together into the water. Trouble was, I didn’t have the traction to get up the ladder with her in one arm. Presto! there was a rope next to the ladder. I grabbed it, not thinking very clearly as to what might happen if we slipped. Ouch.

I had the great fortune, though, to be discovered by an orthopedist who was also at the pool, trying to enjoy the afternoon with his family (until I interrupted things). He kindly relocated my shoulder using the aptly-named traction-countertraction method (just watch the video). Or if you’re easily made queasy, picture a game of tug o’ war — with your arm as the rope.

Shoulder dislocations represent 50 percent of all major joint dislocations, mainly because the shoulder is such an inherently unstable joint. Translation: the “cup” in which the ball of the humerus (arm bone) sits is quite shallow (picture a golf ball on a tee). That’s a far different design than, say, the hip joint, which is buried deep within its cup in the pelvis. As a result, the shoulder is much more mobile than the hip. But freedom always comes at a price.

Following dislocation, I was splinted. (But not before I dislocated it again in the pool, just to illustrate how foolish some patients can be.) X-rays showed I had a somewhat unusual fracture called a bankart lesion, where a little piece of bone breaks off the cup (also known as the glenoid). The larger the fracture, the less of the cup remains intact, and the more likely the shoulder will be pathologically unstable (recurrent dislocation). Again, picture trying to balance that golf ball on a tee that is missing a big chunk — the darn ball keeps falling off.

Need a visual aid? Take a look at my x-ray. The drumstick-shaped humerus is resting next to what looks like a golf tee on its side. Now look and see if you can find where the “tee” is broken. (Email me with your answer — the first 10 correct respondents get a Baskin Clinic pedometer).

With a condition as common as shoulder dislocation, you would think we’d have good data to guide treatment decisions. Alas (as with many other medical diagnoses), the existing research does not always answer the question you are asking.

My orthopedist astutely (if not sensitively) pointed out one thing I had going in my favor: “You’re old.” Older folks have less stretchy collagen fibers, thereby tending to produce stiffer scars when they heal. This helps hold the shoulder in place and makes future dislocation less likely.

But beyond that, I had few reference points — starting with the basics, like the recommended period and position of immobilization. I found studies looking at everything from one week to three weeks of slinging, in positions ranging from internal rotation (forearm resting on the abdomen) to external rotation (forearm out to the side). Bottom line: no clear consensus.

Then there was the whole question of repair versus watchful waiting. It reminded me a great deal of my early (and largely unsuccessful) attempts at dating — do you call her and ask for that second outing, or wait and play a little coy? Both romantic courtship and shoulder therapy have a long way to go in terms of evidence-based research.

I wanted the answer to the question: “For someone my age, how do results differ between treatment (surgery) and no treatment (physical therapy alone)?” What I mostly found was the equivalent of scientific hairsplitting: comparing one surgical technique to another, or one fixation device to another. It’s like going out to breakfast and being offered only variations on sausage and bacon, when you really want to take a look at the pancakes and waffles, too.

I found one article on conservative treatment (written in German) for my type of injury. The study involved only 14 individuals with large fractures like mine. Regardless, the authors reported very positive results: no subsequent dislocations and no development of arthritis over an average of five years. So my surgeon and I crossed our fingers and decided to forgo surgery.

So far I think we have made the right wager. Going in, I was reassured by one statement my surgeon made: “It’s what I would do if it were my shoulder.”

Welcome to the art of medicine.

And allergy season is serious business. Since the ol’ Gipper (that would be President Reagan, for my younger readers) first declared it in 1984, the month of May has been known as National Allergy and Asthma Awareness Month.

Given the stupefying side-effects of antihistamines like benadryl, it’s also no wonder that the Zombie Research Society has also declared May to be Zombie Awareness Month. (Note: not an official presidential designation, despite the powerful zombie lobby.) Then again, given the fantastic number of presidential proclamations that are issued each year, who’s to say The White House could not have slipped it in when no one was paying attention.

Locals always claim the Willamette Valley is one of the worst allergy locations in the country. Yet somehow, Portland ranks among the least affected cities on the Asthma and Allergy Foundation of America’s “Allergy Capitals.” That’s right folks — Stumptown scored a low 89th out of 100 major US metropolitan areas.

My nose would beg to differ, but such is the injustice of composite scoring systems. Just ask the administrators of Reed College, who have been speaking out on the flaws of US News and World Report’s college ranking methodology for years now.

I realize your watering eyes may not be able to take much more of my digressions, so here are my top allergy treatment recommendations:

• Behavioral adaptations should always be first on the list. Exercise indoors, or outdoors only at times of low pollen (usually in the evening). Keep windows and doors shut at all times. Trimming fingernails short and showering after outdoor activity both help to keep pollens off your body.
• If you need allergy medication, the single most effective treatment is nasal steroid spray. I have found that controlling symptoms at the nose provides nice carryover benefits to eye and throat complaints as well. Choice of brand is up to you — they’re basically all the same. So go with the generic fluticasone (Flonase).
• Need more horsepower? Add a sedating antihistamine like diphenhydramine 25mg (generic benadryl) at night. Yes, it makes you sleepy, but you’re going to sleep anyway. And it’s far more effective than claritin or allegra — not to mention dirt-cheap.
• For eye symptoms, use zaditor drops. They’re even OTC to boot, so you don’t need a prescription.
• Still symptomatic? A nonsedating antihistamine like claritin or allegra during the day is my fourth-line recommendation. Your doctor can prescribe several additional medications like antihistamine nasal sprays (astelin), selective leukotriene receptor antagonists (singulair), and even oral steroids (prednisone) if necessary.
• Remember that treatment is additive, so if one medication is ineffective, you add to it a second drug, then a third, and so on.
• For those whom medication does not help, allergen injection immunotherapy (allergy shots) is a proven treatment (but time-consuming and expensive).
• Lastly, forget honey therapy. Honey was found to be ineffective in a well-done (though small) study of 36 allergy sufferers. Participants were randomized to a daily tablespoon of either local raw, nationally processed, or artificial honey supplements. There was no difference in patient-reported symptoms over a 180-day monitoring period.

A lot of folks were hoping the IOM would stretch the available data a little and create some controversial guidelines — imagine a Charlie Sheen/Lindsay Lohan hookup for the scientific community. But they played it much more Tom Hanks and Rita Wilson — solid, dependable, but let’s face it: nothing to make us race to the newsstands.

Vitamin D, as I mentioned in a previous post, has been touted as a preventive for everything from certain cancers to depression. As a result, some advisory groups recommend D in massive doses, with the goal of achieving high blood levels.

But a close review of the science shows most of these studies are associative at best. The New England Journal of Medicine, in an April 14, 2011 editorial, cautions:

“Association therefore cannot prove causation. Many micronutrients that seemed promising in observational studies (e.g., beta carotene, vitamins C and E, folic acid, and selenium) were not found to reduce cancer risk in randomized clinical trials, and some were found to cause harm at high doses.”

Until further data are available, steer clear of megadoses of vitamin D (those in excess of Institute of Medicine recommendations) and aim for a total 25(OH)D (also known as 25-hydroxyvitamin D) blood level of 20 ng/ml — despite what other groups might advise.

On to the common cold….

It’s still mighty chilly in Portland, and that means we’re all inside more and passing germs around with greater ease. If it makes you feel any better, not even your doctor has been spared. The Baskin household has been a rhinovirus revolving door since November.

A recently-published meta-analysis revived interest in zinc, the nutritional supplement that (in nasal form) was associated with numerous cases of anosmia a few years back. In response, the maker, Matrixx, pulled the formulation, while maintaining its safety.

But the oral form of zinc was never implicated, and remains on the market. The new study summarizes all available information since 1984 on zinc and colds, and offers the following conclusions:

• Zinc is an effective cold remedy in adults and children, shortening duration and severity of cold symptoms if taken within 24h of symptom onset.
• When used as a preventive in school-age children, zinc also reduces absenteeism associated with colds.
• If taken continuously for 5 months, zinc cuts cold frequency by about a third.
• No one knows how zinc works to fight cold viruses.
• Zinc causes mild-to-moderate side effects, including bad taste, nausea, constipation, diarrhea, abdominal pain, dry mouth and oral irritation.
• Studies used a wide variety of formulations (zinc gluconate or acetate lozenges, zinc sulfate syrup) and dose ranges (30 to 160 mg/day), so the optimal regimen is unknown.

This meta-analysis was conducted by the highly respected Cochrane Group, so I’m inclined to trust the methodology.

Whether it’s worth it to take a pill that tastes bad, causes a fair number of side effects and reduces cold duration by only a day is up to the consumer. For individuals who catch a lot of colds, that one-third reduction in cold frequency might be sufficient reward to suffer through preventive treatment for a season.

As for me, I’ll stick with chicken soup.

The common cold is usually caused by one of the many rhinoviruses — a family of 110 distinct strains, though additional virus families, such as coronoviruses, bring the total to over 200 strains. Understanding this disease process is complicated by the fact that there is no good animal model for experiments. In other words, not many critters catch colds.

This has not stopped researchers from attempting to infect the usual suspects: mice, rats, hamsters, rabbits and the like. Further efforts with hedgehogs, voles, ferrets, and a variety of primates from the red patas monkey to the sooty mangabey failed as well, leaving researchers with no other option than to work with the often reluctant and unreliable homo sapiens sapiens. Trust me, they drive a much harder bargain than those capuchin monkeys who work for grapes.

Despite these setbacks, we do know a few secrets of the common cold:

• Colds are not caused by exposure to cold or wet weather.
• Children are a prime vector for cold transmission, probably because of their close contact in schools (and often suspect hand hygiene).
• Colds transmit better in close quarters, which may explain the seasonal spikes at the start of school and the onset of cold weather (both drive people inside).
• Cold viruses can live up to 3 hours on your skin. They can also survive up to 3 hours on objects such as telephones, stair railings, Legos, Thomas trains, and anything manufactured by Mattel. (I’m just kidding about those last three, but it’s probably true anyway.)

Let’s move on to treatment. The rows and rows of cold medications on display at any drugstore have such potential for toxicity (combined with limited clinical value) that the medical community increasingly recommends against their use in the most frequent group of cold sufferers — children. I would echo that recommendation for their parents, too. The stuff just doesn’t work.

Other generally ineffective “natural” remedies include vitamin C, echinacea, garlic, and a variety of Chinese herbs.  Three others deserve special mention:

• Airborne, that ubiquitous combination vitamin preparation, was sued by 32 attorneys general in 2008 (for comparison, 41 states sued the tobacco companies in the late 1990s) for false advertising.
• The makers of Emergen-C, wary of Airborne’s experience, have resorted to the highly unscientific gimmick of customer testimonials. You can read Meghann’s achingly vague claims of benefit here.
• zinc nasal preparations have been associated with permanent loss of smell, prompting the FDA to issue a warning against their use. Oral forms of zinc have also been researched and results are contradictory in the two most recent studies.

But I shouldn’t throw stones, since my own routine (chicken soup, ibuprofen, sinus rinsing, and a nighttime humidifier) is also largely unproven, with exception of the ibuprofen.

If you absolutely need medication for cough, only one thing works: hydrocodone. Unfortunately, hydrocodone has high abuse potential and has gained quite a following in certain circles (Purple Drank, anyone?). Side effects can also limit its effectiveness.

As for prevention, our weapons are few. Good handwashing is a must, but for heaven’s sake avoid those antibacterial soaps. Alcohol-based gels are effective when a sink is not available. There’s also evidence that insufficient sleep leads to more colds, so try and get at least 7.5 hours of sleep nightly. Which is why I am going to end this posting here, since it’s past midnight and I have to get up early tomorrow.

So it would make sense that Americans apply the same logic to medical imaging. Unfortunately, we are in a much grayer (read: charcoal) area when it comes to the diagnostic value of all those studies. Most medical imaging comes at a price: ionizing radiation, a known carcinogen. (Though for some reason, the US Department of Health and Human Services did not officially recognize radiation as carcinogenic until 2005 – go figure.)

We used to take a fairly casual approach to those nifty little waves of energy that pass right through you. My mom tells amazing stories of the Buster Brown “shoe fitter” — an actual fluoroscope that was deployed in stores to ensure a proper fit. Kids were so entertained by the devices they used to stand on them repeatedly, fascinated by the moving images of their tiny irradiated toes.

The amount of radiation exposure from, say, a chest CT scan (equivalent to about 70 conventional chest X-rays) really only becomes significant if patients are receiving lots of studies. But this happens more often than you might imagine. Yes, trauma patients get scanned a lot, but so do patients with less life-threatening problems like chronic abdominal pain.

How much radiation are we talking about? The National Council on Radiation Protection and Measurements, a federally chartered agency, has been pondering issues surrounding radiation exposure since 1964. Granted, this is the same federal government that was also doing above-ground nuclear testing with reckless abandon until 1963. Their motto then: “Strontium-90 — we’ve added it to your milk!” But I digress.

The NCRP publishes riveting titles like Report #154: Cesium-137 in the Environment: Radioecology and Approaches to Assessment and Management. But occasionally they hit the jackpot and get the kind of recognition all physicists long for. Report #160 was just such a document. Quite simply, it was the first time anyone had taken a systematic look at radiation exposure in the US in more than 25 years. Some highlights:

• Medical imaging now accounts for nearly half (48%) of total US resident radiation exposure, up from 15% in the 1980s.
• CT scans represent 50% of total medical radiation exposure, up from 3% in the 1980s.
• In 2006, US doctors performed CT scans at four times the rate in the UK.

And sadly, much of this testing has little or no medical justification. Explanations for increased imaging rates include:

• Financial (doctors who own their own imaging equipment order tests at rates up to 7 times that of doctors who are not owners)
• Laziness (doctors who order imaging may avoid conflict with patients and/or shorten appointment duration/complexity)
• Fear of malpractice
• Patient preference and direct-to-patient marketing (“whole body” CT scans and heart scans)

So the next time one of your providers suggests a quick trip through the scanner, ask him or her if it’s really necessary. Not only will you impress your doctor with your thoughtfulness, you might just save your body a little damage.

Four points emerge from the presentation, given by experts from several branches of the National Institutes of Health:

• There are only two systematic reviews (from 2008 and 2010) of vitamin D and its benefits. Both conclude there are no data to prove or disprove claims that D can influence the course of heart disease, cancers, hypertension, pregnancy outcomes, or death rates in general (cheerfully referred to as “all-cause mortality”).
• The existing recommendations on D blood levels and intake come from an Institute of Medicine report from 1997. That’s OLD research. The recommendation of 27.5 nmol/L was only intended to prevent rickets and other severe deficiency states. Because of this, other organizations have stepped in with their own guidelines — some as high as 80 nmol/L — though no one is sure which is correct.
• Because no one knows what the correct blood level should be,  the scope of the deficiency problem cannot be defined. For example, if we use the 27.5 nmol/L level, less than 6% of the US population is deficient. But raise that to 80 nmol/L, and all of a sudden that figure rises to more than 70%.
• The assays to measure D levels have changed dramatically over the past 15 years, and no one is sure which one is the most accurate.

As the Director of the Office of Dietary Supplements, Dr. Paul Coates, succinctly stated:

“I don’t know what number to tell people to shoot for… oh, and I don’t know that that number is reliably measured. It may be, but I don’t know that.”

Donald Rumsfeld could not have spoken any more clearly.

For now, I think the most reasonable recommendations are:

• 400 IU daily in children
• 400-800 IU daily in men and women < age 50
• 800-1000 IU daily in men and women > age 50.

We’ll see what the next Institute of Medicine report advises. Try not to lose any sleep in the meantime.