Obesity Myth #3: You Can Reverse and Prevent Obesity with a Healthy Diet

By Stewart Lonky, M.D.

Here’s a frequent headline: Eating a healthy diet will reverse and prevent obesity

On the surface, the statement seems to make sense. After all, few obese people got that way by subsisting on a diet of vegetables, fruit, and lean protein. Ambitious marketers and would be diet gurus know this, and many spend their days scouring the globe for the next greatest thing to help us lose weight. Some latch onto a clever name or catchy hook they know desperate dieters will find irresistible. Others will pick a location where longevity or fewer illnesses appear to be the rule, and then sell whatever those folks are eating, assuming it’s the source of their continued good health. 

You’ve probably all heard of the Mediterranean diet and the so-called Blue Zones, where National Geographic fellow and New York Times bestselling author Dan Buettner says residents live longer and are healthier than average. So, is the key to ending obesity and lasting weight loss to toss everything you’re eating and only consume what the residents of these regions include in their daily diet? 

The answer is a resounding “no.” There are plenty of obese and overweight people in these countries and regions. Just look at the obesity rates in the following Mediterranean countries and Blue Zones. One even exceeds the U.S. obesity rate:

• Greece 22.3 percent (Greece has the 11th most obese citizens in Europe)
• Spain: 26.6 percent
• Turkey 27.8 percent 
• Cyprus: 25.5 percent
• Croatia: 24.2 percent
• Slovenia: 28.6 percent
• Italy: 42 percent (Sardinia has a 15 percent obesity rate)
• Malta: 25 percent

These numbers are even worse for kids. Countries in the Mediterranean region now have the highest rates of childhood obesity in Europe, according to a report from the European Congress on Obesity. In fact, six Mediterranean countries ranked among the top 10 in overweight/obesity rates among children ages 5 to 9, with Italy (42 percent), Greece (41 percent), and Malta (39.9 percent) topping the list. More than 36 percent of children in Spain and Cyprus were also found to be overweight.

It’s also worth mentioning that the major principles of the Mediterranean and Blue Zone diets are neither new nor indigenous to these regions.  Consuming lots of fruits and vegetables, avoiding processed foods and artificial ingredients, limiting saturated fat, sugar, and salt intake, and practicing moderation, which seldom works for most people with weight problems, all are habits to which millions of people around the world adhere. There are also plenty of people in Mediterranean regions and Blue Zones that don’t practice these habits. 

In Okinawa, one of the world’s seven Blue Zones, many people eat a high-carbohydrate diet that is relatively low in fat and protein when compared to another popular diet, Keto, as well as many other diet programs. What separates the Okinawan diet from other popular diets isn’t merely the food, but the calorie content. Okinawans, as an example, eat about 15 percent fewer calories than mainland Japanese. They also consume 50 percent less rice and only get one percent of their daily calories from fish and less than one percent from non-fish/seafood meat sources. 

In animal models, calorie restriction is the only proven way to extend lifespan. And the Okinawans just eat a lot less food than mainland Japanese. This may, or may not, have something do with their extraordinary longevity and comparatively low overweight and obesity rates. While a reduced-calorie diet might help an overweight person from becoming obese, it’s not enough to reverse obesity.

What we also know is that even the healthiest diet isn’t enough to save this country’s 94 million obese adults. In a paper published in the Lancet, researchers argue that calorie restriction triggers several biological adaptations designed to prevent starvation. “And these adaptations might be potent enough to undermine the long-term effectiveness of lifestyle modification in most individuals with obesity, particularly in an environment that promotes energy overconsumption.” 

Simply, when someone becomes obese, his or her body acclimates to the new weight. When a low-calorie diet or another form of self-imposed famine is put in place, biological mechanisms kick in cause the body to defend itself as if it were in starvation mode. It resists giving up the excess weight.

There’s a reason why dieting alone seldom helps obese people lose weight, much less helps with long-term weight loss. Most nutrition studies suck; they are notoriously unreliable, their data coming from self-reporting, which anyone who knows even a little about human nature knows is questionable. The problem is that there’s no other way to study nutrition in people.

Only one study, the Minnesota Semi-Starvation Experiment, embarked upon to learn how to re-feed starving people at World War II’s conclusion, came close to explaining what happens to our bodies when we restrict calories. In the study, perfectly healthy men who’d never attempted weight loss were given an average of 1,800 calories a day (more than some weight-loss diets suggest). 

Following the experiment, these once healthy men experienced severe psychological problems, temper tantrums, violent outbursts, and extreme food obsessions. Even after the experiment was over, the men experienced lifelong changes in desires and attitudes around food. When, as an example, they were allowed to eat normal amounts, most of the men couldn’t follow basic hunger cues, such as knowing when they were full. They also reported frequent binge-eating bouts. One man even broke the diet with a steady stream of ice cream sundaes and malted milkshakes.

Perhaps the most critical point to consider is that obesity is never about one thing. Obesity is a complex, multifactorial disease that develops from the interaction between genotype and the environment. While our understanding of how and why obesity develops is incomplete, we know it involves the integration of social, environmental, epigenetic, behavioral, political, cultural, economic, physiological, metabolic, and genetic factors.

How can we expect to fix something as complex as obesity with diet alone?

Think about how ridiculous it is to suggest to someone that eating nothing but bacon, cabbage, or assigning points to food will reverse the dozens of factors that contribute to obesity?

As the wonderful Bruce Y. Lee writes in Forbes, “Obesity is a sign or symptom that the systems around us are broken. Obesity is not an individual problem. It’s a systems problem.” And as Dr. Lee points out, there are dozens of internal and external systems that cause obesity. 

Until we accept that obesity is not a simple problem, the proper methods, approaches, and solutions will continue to elude us, and the obesity epidemic will continue.