The diet dilemma

Hutch News

The diet dilemma

In a landscape crowded with contenders that each promise better health, how do you choose the best eating plan?

Jan. 21, 2015
Science beakers

How do we sort through the confusion to find an eating plan that works for us – and still makes good scientific sense? We asked top experts at Fred Hutchinson Cancer Research Center and elsewhere for their opinions.

Illustration by Kimberly Carney / Fred Hutch News Service

When Angela Smalley decided to go on a diet earlier this month, it wasn’t about squeezing into a smaller dress size by March (although she admits that would be nice). It was about maintaining her health for the long haul.

“I’d like to take care of my body now rather than have to be reactive to problems that might come up as I age,” said the 47-year-old Seattle marketing executive of her recent switch to an eating plan that restricts carbohydrates, sugar and dairy and loads up on vegetables and lean protein. “I don't have any health problems right now, and I'd like to keep it that way.”

When we’re in our 20s and 30s, we diet to fit into wedding dresses, interview suits and that favorite pair of skinny jeans. But as we get older, studies show that our goals shift and become less about how we look and more about how we feel – or want to feel – for the rest of our lives. We diet to lower blood pressure and cholesterol, and to try to fend off cancer, diabetes and heart disease. Sure, we want to “look good naked,” as Kevin Spacey famously said in the film “American Beauty,” but we also want to improve our overall health and longevity.  

And we look for eating plans to help us accomplish this. Unfortunately, the diet landscape is crowded with contenders, each one promising better health and longer life by lowering our glycemic index, raising our alkaline level or reducing our oxidative stress through a handful of Fabulous Miracle Superfoods! We’re blinded by science; we’re blinded by pseudoscience. And every 10 minutes a new study comes out that turns the last one on its head.

How do we solve this diet dilemma and find an eating plan that works for us – and still makes good scientific sense? We asked top experts at Fred Hutchinson Cancer Research Center and elsewhere for their opinions.

Variations on a theme

The U.S. News & World Report 2015 Best Diets Rankings, released earlier this month, may be one place to start.

The annual list is a comprehensive assessment of the best eating plans with regard to weight loss, nutrition, safety, disease management and ease of use, as determined by a panel of nationally recognized experts in diet, nutrition, obesity, food psychology, diabetes and heart disease. This year, the panel evaluated 35 popular diets and divvied them into eight categories – everything from Easiest Diets to Follow to Best Heart-Healthy Diet to Best Overall Diet.

“There’s definitely a difference with diets now,” said Dr. Teresa Fung, a nutritional epidemiologist and professor at Simmons College in Boston who has served on the U.S. News expert panel for the last few years. “Fifteen or 20 years ago, it was all about how you can drop weight quickly. But now we’re beginning to accumulate enough data in terms of how people eat and how they can prevent disease.”

And that data – much of it culled from research funded by the National Institutes of Health – is forming a much clearer picture of how we can stave off obesity and chronic disease.

“If you look at the top diets for healthy eating or the best diets overall, they’re based on good science,” she said. “There are slight differences in terms of the quantities or the type of food you focus on, but there’s a lot of overlap in terms of how you should focus on low portion size, plant protein, minimally processed fruits and veggies and whole grains. These diets will make a difference in terms of health. People can’t expect to follow them for three weeks and see a drastic change, but there will be gradual improvement.”

'DASH' diet No. 1 overall

This year, top dog in the Best Diets Overall category was the DASH diet, aka Dietary Approaches to Stop Hypertension, an eating plan developed by the National Heart, Lung, and Blood Institute to prevent high blood pressure. The DASH Diet, which promotes a high intake of fruit, vegetables and whole grains, a moderate intake of lean poultry and fish and a limited intake of salt, also came in as No. 1 in the Best Diets for Healthy Eating and tied for first in the Best Diabetes Diets category.

Also ranked high:  the Therapeutic Lifestyle Changes (TLC) diet developed by the National Cholesterol Education Program, the Mayo Clinic diet, the Ornish diet, the Mediterranean diet, the Weight Watchers diet, and the Biggest Loser diet, all of which promote many of the same principles – for instance, loading up on fruits and veggies and sticking with lean protein – with a few extra behavioral add-ons like calorie tracking and/or food journaling.  

These same diet basics were highlighted by Dr. David Katz, a public health researcher at Yale University, who attempted to cut through the “clutter of competing claims” in a recent paper of his published in the Annual Review of Public Health, “Can We Say What Diet Is Best For Health?”

“The weight of evidence strongly supports a theme of healthful eating while allowing for variations on that theme,” he wrote. “A diet of minimally processed foods close to nature, predominantly plants, is decisively associated with health promotion and disease prevention.”  

Quibbles and questions

A bit of a DIY dieter, Smalley doesn’t follow a specific plan like the Ornish or TLC or DASH, but instead, she adheres to a few guidelines that have worked for her in the past. 

“From years of experience I know what works best for me when I need to lose weight,” she said. “So I try to limit the amount of sugar and dairy as a general rule. And I’ve found that cutting out carbs really works for me, too. I generally try to steer away from ‘diets’ and just follow basic principles of healthy eating. And once I get in the groove of eating like this, I try to keep with it for the long term.”

The problem, of course, is finding a few basic principles that don’t change every time you read the health news.

Dr. Mario Kratz, a Fred Hutch public health researcher whose focus is the relationship between diet and disease, acknowledges that the field of diet and nutrition is ever-evolving, and that there are many questions that remain when it comes to the quest for a diet that will keep chronic diseases at bay. For the past few years, he’s been investigating whether low-fat dairy is truly better than full-fat dairy and said there are other areas of inquiry where a definitive answer is just out of reach.

The Ornish diet, for instance, has been shown to be effective at reducing heart disease (it came in first on the U.S. News Heart-Healthy Best Diets list). But Kratz wonders whether it’s the diet itself – a combination of complex carbs, veggies and lean proteins – or whether other factors come into play.

“[Ornish’s] interventions were multifactorial,” said Kratz. “People also exercised more, started to meditate and had group sessions to speak about their feelings and relationships. These are all great things, but it makes it hard to know how important each individual piece is to the prevention of heart disease.”

Kratz has questions about the DASH diet, too. He absolutely agrees that it’s a largely healthy diet due to its major emphasis on fruits and vegetables and de-emphasis on sugar and sugary beverages.

“These are undisputed pieces of health advice that are well-supported by evidence,” he said.

But he wonders if it might be the overall healthy nature of the diet – and not the drastic reduction in salt – that actually lowers blood pressure, pointing to studies that show sodium reduction alone may not be the key to reducing hypertension.

“You may say it’s splitting hairs, but personally this is an important point because most people will struggle with that single aspect of the DASH diet,” he said. “It’s hard to cut back on salt that much. If we know from other studies that the sodium reduction by itself probably has a minor effect on blood pressure, it may help to know that  [people] can follow the diet but use the salt shaker more frequently. It certainly makes the other dishes – like vegetables – more palatable.”

A bit of wiggle room is OK

In other words, there’s a bit of wiggle room, although it definitely depends on where you wiggle.

“If you wiggle with three servings of soda a day, that’s not so good,” he said. “In fact, if you want to make one change in dietary habit that will clearly benefit you with regard to the reduction of disease, it’s reducing your intake of sugar-sweetened beverages like fruit drinks, energy drinks and soda.”

As a public health researcher, Kratz admits there is much work to be done. But he encourages people to not become frustrated by scientific finessing and instead, to focus on the big picture.  

“If you focus on the similarities of these diets, you get a good sense of the key elements and how you should be eating,” he said. “People would do well to increase their consumption of fruits and vegetables and legumes and whole grains and reduce their consumption of processed food, refined grains and sugars.” 

And if you want to add a dash of salt to that DASH diet, go for it.

Diane Mapes is a staff writer at Fred Hutchinson Cancer Research Center. She has written extensively about health issues for NBC News, TODAY, CNN, MSN, Seattle Magazine and other publications. A breast cancer survivor, she also writes the breast cancer blog doublewhammied.com. Reach her at dmapes@fredhutch.org.

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