The New Year brings an inevitable flood of fitness and diet fads, a great slosh of suggestions on how to do things —  lose weight and get fit v that we already know how to do.

What will 2014 bring? Will a new evil food be identified as the source of all our weight-gain problems? (Perhaps this year it will be lettuce? With all its leafy limpness, it seems a good target.) Which macronutrient is to be avoided and which deemed beneficial? (In the latter I’m pulling hard for fat.) Will a new vitamin emerge as a cure-all for everything from obesity to a flagging sex drive? And what will be the new form of exercise that will transform us from pudgy and soft to toned and tight? (Idea: subzero yoga. The shivering will burn extra calories, and just think of the market potential of yoga parkas!)

I have been following diet and fitness fads for years.  History —  and for that matter, science —  provides a clear message: these trendy approaches will not work.  They never do. Period. Full stop.

Can you name a single diet fad, just one, that has been effective, long-term?

Indeed, research on the performance of diets is grim.  Studies have consistently found that the vast majority of people can, at best, sustain only modest weight loss, regardless of the type of diet used. In these studies, successful weight loss is usually defined as keeping off 5-10 percent of a person’s initial  weight —  not exactly the beach-ready transformation promised by many diet fads.

A well-known study published in American Psychologist in April 2007 carefully analyzed 20 of the most methodologically sound dieting studies to get an idea of how many people actually keep the weight off for two or more years.  They found that the average weight loss was around two pounds, and that a large portion of the individuals actually put on more weight than they lost. The study’s authors came to the blunt conclusion that dieting simply does not work.  Indeed, they suggest that ”the most positive conclusion is that dieting slows the slight weight gain that occurs with age among the average non-dieter.”

Given that over half of Canadians are obese or overweight, it’s not surprising that they are looking for answers to the profound challenge of weight loss. But diet trends seriously confuse the health message, exploiting the disheartening reality that losing weight and keeping it off is tough and requires a sustained and sustainable lifestyle adjustment.

What is most frustrating about the rise of these yearly diet and fitness trends is that the vast majority of them market an approach that is exactly wrong.  Invariably, the focus is on aesthetics —  sexy abs, a tiny dress size, and so on —  rather than good health. No wonder. The social pressures are enormous, and research backs up this impression. One study, published Health Communication in July 2013, examined over five thousand pages of popular women’s health and fitness magazines, including Fitness, Self, Shape, Health and Prevention. It found (no surprise here) that weight loss and body shaping were major topics in these magazines, leading to a focus largely on appearance as opposed to health.

Sustained weight loss requires lifestyle modifications that must be maintained…well, forever. But other themes associated with diet and fitness trends include less-than-helpful promises of quick results, and a narrow focus on the ”miracle” benefits of a particular kind of food or way of eating. Quick results are usually associated with a radi-cal approach, such as the popular and (from a scientific perspective) absurd cleanses that involve a ridiculously restrictive diet. The ”Master Cleanse,” currently the rage in Hollywood, involves the consumption of little more than lemon juice, maple syrup and cayenne pepper. Will you lose weight on this diet?  Yes. Will you put it all back on when you can no longer live on a diet of spicy, sticky, citrus beverages? You bet.

Confused messages about diet and nutrition also come from more legitimate sources, including the scientific community. Indeed, each new nutrition study that touts the possible benefits of a particular food —  almonds, blue-berries, red wine, chocolate —  seems to generate a significant amount of media coverage. ”The Chocolate Diet?” read a 2012 New York Times headline, after the release of a new study correlating chocolate consumption with weight loss. These confused messages occur partly because the authors and research institutions inappropriately hype the results of their work. The American Journal of Preventive Medicine published a report in November 2013 that examined almost 1,000 studies, and concluded that ”over-reaching in presenting results in studies focused on nutrition and obesity topics is common in articles published in leading journals.”

Such studies may, in the long run and after replication, add a bit of knowledge to our overall understanding of nutrition. But they are rarely significant enough to warrant a change in how we eat. Human biology is complex stuff.  Food is complex stuff. And our food environment —  a host of variables from family background to school cafeterias, advertising, the workplace and restaurants —  is monstrously complex. It is unlikely that one simple magical solution to our diet woes can account for all these factors.

From a public health perspective, we should keep the nutrition message simple, consistent and evidence-based. This seems the only way to combat the sea of pseudo–scientific and confusing garbage that permeates popular culture.

Here is a good place to start.

Research tells us that few Canadians know how many calories they should be consuming. Likewise, few of us eat enough fruits and vegetables, despite their well-established health benefits. A large August 2013 study from Sweden of over 70,000 people, for example, found that eating fruits and vegetables was associated with a longer and healthier life (American Journal of Clinical Nutrition).  Another massive August 2013 study published in the American Journal of Epidemiology followed almost a half a million people and found a similar reduction in mortality, particularly in the context of cardiovascular disease.

Let’s make 2014 the year of these two straightforward and health-oriented messages:

  • Half of what goes in your mouth should be a real fruit or vegetable (for a slogan, how about “50 F∕V”?).
  • We should strive to learn how many calories are appropriate for weight maintenance (a diet diary is a great strategy).

So ignore all the diet hype, at any time of year. Ignore too-good-to-be-true weight-loss strategies that fill consumer magazines and airtime on cable. They don’t work. Just eat smart. For 2014 and beyond.