Few things captivate the public more than a new diet.  From Atkins to Ornish to the Mediterranean diet, each new theory attracts attention and true-believer adherents and generates lots of book sales and interviews on daytime TV.  People passionately argue about whether a diet low in carbohydrates or low in fat is best for weight loss.  But until now no large trial has ever been done to answer the question.

This week’s New England Journal of Medicine published the largest study that directly compares different diets to measure which yields the greatest weight loss.  Over 800 overweight adults were randomized to one of four different diets.  (Importantly, diabetics were excluded.)  They were all given diets calculated to provide 750 calories fewer than they were burning daily, but the four diets differed in the percentage of calories from fat, protein, and carbohydrates.  Two of the diets were low-fat and two were high-fat.  Two were average-protein and two high-protein.  And the four diets provided a broad range of carbohydrate intake from low to high.

The participants were also asked to participate in periodic group counseling sessions and were instructed to do 90 minutes of moderate exercise per week.  They were followed for 2 years and their compliance with group attendance, diet and exercise was tracked.

Interestingly, the four diet groups lost weight at the same rate.  Six months into the study the participants lost an average of 13 lb, 7% of their body weight.  After that, on average, they slowly regained weight, so that by two years the average weight loss was 9 lb, the same in all four groups.

So diet and exercise lead to weight loss, and whichever low-calorie diet you can stick to is as good as any other.  So get started.  You can still buy the latest diet book and swear that it’s the best because your favorite actor lost weight on it.  Only you and I will know that you owe your success to the New England Journal of Medicine.

Learn more:

New England Journal of Medicine article:  Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

NY Times article:  Study Zeroes In on Calories, Not Diet, for Loss

Quitting smoking is probably the hardest thing I ask my patients to do.  (Losing weight is probably the second hardest.)  Smoking is a profound addiction.  Smoking feels good, and countless smokers have told me the calming pleasure they get from a cigarette.

Despite the health risks and financial costs associated with smoking, medications aimed at helping smokers quit have been only modestly successful.  A very helpful article in Monday’s Los Angeles Times reviews the medications available to assist in quitting smoking.  If you smoke, I urge you to read it.  (See the link below.)

The oldest quitting aid is nicotine replacement.  Nicotine is available over-the-counter as a patch, gum, lozenge or inhaler and has long been known to help some smokers kick the habit.  There is some new information that makes nicotine replacement even more effective.  It was previously thought that smoking while using nicotine replacement (for example smoking while wearing a nicotine patch) was very dangerous.  It turns out to be quite safe (or no more dangerous than just smoking).  The reason this option is helpful is that new studies show that many smokers prefer to quit slowly, by gradually decreasing the number of cigarettes smoked.  So smokers can now use nicotine replacement during the slow weaning period rather than have to quit smoking abruptly.  A recent study in the American Journal of Preventive Medicine showed that for smokers gradually decreasing their cigarette use over an 8 week period, nicotine gum during that time led to more successful tobacco abstinence than placebo gum.

There are also newer prescription medicines for tobacco cessation.  Zyban (buproprion) is the same medicine as the antidepressant Wellbutrin.  Studies have shown that it helps smokers quit more than placebo.  Like all antidepressants it can have some side effects.  The newest option for smokers is Chantix (varenicline) which I wrote about when it became available in 2006.  Chantix, however, is plagued by new reports of psychological side effects, like depression.

The bottom line is that neither of these medicines is spectacularly effective.  In the studies proving their effectiveness, most smokers in both the placebo and medication group went back to smoking, but the medication group did better than the placebo group.  So you have to be determined, and you have to try more than once to finally quit successfully.

If you’re a smoker, discuss these options with your doctor, and take a look at the articles below.  2009 may be your year to quit.

Learn more:

Los Angeles Times article: Ready to quit smoking?

American Journal of Preventive Medicine article: Quitting by Gradual Smoking Reduction Using Nicotine Gum: A Randomized Controlled Trial

New England Journal of Medicine article: A Randomized, Controlled Trial of Financial Incentives for Smoking Cessation

My post about Chantix:  Chantix is Modestly Helpful for Quitting Smoking

Our modern hyper-efficient means of producing, processing and distributing food has made hunger virtually extinct in the developed world. (In fact obesity is a much more pressing problem.) But our modern food production network is revealing an increasingly dangerous cost. Because food from any one farm or any one plant is frequently distributed nationally or even internationally, contamination with a foodborne infection can sicken thousands before the source is identified.

Two years ago Escherichia coli from contaminated spinach caused a nationwide outbreak. This spring and summer an outbreak of Salmonella traced to contaminated peppers imported from Mexico led to over 200 hospitalizations and 2 deaths. Most recently, in an outbreak that is still ongoing and is receiving heavy media coverage, Salmonella linked to contaminated peanut butter and peanut paste has caused hundreds of hospitalizations and at least 8 deaths.

A perspective article in the New England Journal of Medicine attempts to propose sensible solutions to an increasingly dangerous, expensive, and frequently lethal problem. The author is dismissive of organic back-to-nature fantasies:

To those who believe that the solution is a return to a pastoral, early-20th-century model with millions of small farms producing more “natural” food, I would point out that even if the millions of farm workers who would be required were available to produce food on a quasi-boutique scale, the costs would be enormous; it would be impossible to feed 300 million Americans, let alone the rest of the world. Efficient, industrialized production of huge quantities of food is an inescapable necessity to avoid food shortages and global famine. The challenge is to enhance the quality and safety of industrially produced food.

Instead he proposes improved inspections, information technology for foodborne infection reporting to allow rapid identification of an outbreak, and bar-coding of perishable foods so that the farms and factories that grew and processed the food are immediately identifiable.

He also recommends an idea that I wrote about last summer which would prevent up to a million cases of foodborne illnesses in North America annually. All high-risk food should be irradiated. The only obstacle preventing this is widespread public misunderstanding and fear of irradiation.

Learn more:

Track the latest recalled products on the US FDA Salmonella page

Associated Press article: Texas recalls all items from plant over salmonella

New England Journal of Medicine article: Coming to Grips with Foodborne Infection — Peanut Butter, Peppers, and Nationwide Salmonella Outbreaks

My previous post on food irradiation: Gamma Rays are Good for Your Veggies

Tangential miscellany:

Two extraordinary men were born 200 years ago yesterday. One was Abraham Lincoln. If you haven’t read it recently, take this opportunity to read the Gettysburg Address.

The other man was Charles Darwin. I’ll close with a quote from the last page of his landmark work On the Origin of Species which was published in 1859.

It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us… Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life… that … from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.

The good news about this flu season is that so far, both nationally and in California, it has been a mild one, with a relatively small number of people infected.  The weekly trends are still increasing, so the worst is still ahead of us.

The bad news is that one of the major strains of the flu virus this season is resistant to Tamiflu, the most frequently prescribed and safest anti-flu medicine.  In response, the CDC has issued an Interim Antiviral Guidance statement, which recommends which antivirals should be used this season.  The recommendations are impractically complex, and depend on the availability of rapid testing to identify the strain infecting each patient.

The most practical solution for this flu season is to use Relenza, an inhaled anti-flu medicine that is as effective as Tamiflu and to which this year’s strains are all sensitive.  Relenza should be avoided, however, in patients with asthma or emphysema.  Like Tamiflu, Relenza should be started within the first 48 hours of symptoms.  So if you get a high fever, diffuse aches, and a cough, call your doctor right away.

But the good news is that it’s not too late to get your flu shot.

Learn more:

Track the influenza season in California:  California Influenza Surveillance Project

Tack the influenza season nationally so you can warn Aunt Martha in the Midwest:  Centers for Disease Control Flu Activity and Surveillance

Follow the epidemic on Google which detects flu activity about two weeks earlier than traditional surveillance:  Google Flu Trends

LA Times article:  Tamiflu no longer works for dominant flu strain