Registered dietitian and nutritionist Jill Weisenberg shares the process and results behind US News & World Report's annual Best Diet Rankings.
Every year in January, US News & World Report comes out with their ranking of popular diets. It contains the details and data around a few dozen of the most popular diet plans. The diets are ranked from best to worst overall and in a number of sub-categories like heart health and weight loss. Behind these diet ratings is an expert panel of nutritionists, dietary consultants, and physicians specializing in diabetes, heart health, and weight loss.
Joining me today to discuss the results of this year’s rankings is my colleague, Jill Weisenberger. Jill is a registered dietitian nutritionist and certified diabetes educator. She’s the author of four books, including her most recent, Prediabetes: A Complete Guide.
Jill was also a member of the panel of experts that rated the diets this year for US News and World Report. So I thought it would be interesting not just to talk with her about the results but get a behind-the-scenes peek at the process.
Here are some highlights from our chat, but I encourage you to click on the audio link to hear the entire conversation.
Nutrition Diva: What's the process by which the panel ranks the diets each year?
Jill Weisenberger: A lot of people ask if we meet as a group and hash things out, but that's not the way it's done. We work on our own. The folks at US New provide a profile for each diet along with research summaries. And I've been a dietician and a diabetes educator for many, many years. So, we answer the questions based on the research as well as our own experience. It's a very long survey about how each diet holds up against general healthy eating principles, what we think it will do in terms of weight loss, heart health, diabetes, and that type of thing.
ND: Topping the overall rankings this year was the Mediterranean Diet, which has been at or near the top of the list for years. Other diets in the Top Ten included the DASH diet, Flexitarian Diet, the MIND diet. In your view, what do the top-rated diets seem to have in common?
The top diets all tend to be more whole-food-based. They may not be vegetarian and they aren't vegan, but these diets definitely have a plant slant.
JW: The top diets—particularly the top three—are very, very similar. They all tend to be more whole-food-based. They may not be vegetarian and they aren't vegan, but these diets definitely have a plant slant. It doesn't surprise me which ones rank at the top.
ND: Another thing that these top diets had in common is that they were not so much a set of rigid dietary rules or a specific meal plan that you had to follow, but more a guideline, a set of eating habits, almost a lifestyle approach.
JW: I would agree with that for sure. The one that's probably the most prescriptive would be Dash because, as I know you're aware, that was a diet that was designed by the NIH is a research tool originally to look at how we can lower blood pressure. So that one is probably the most prescriptive, but even that one has a lot of flexibility in it.
ND: So, at the other end of the list for overall best diets were the Atkins diet, the Dukan diet, and the ketogenic diet, which are all very low carb approaches. But I noticed that some of the other things at the bottom of the list were things like the raw foods diet, paleo, and Whole 30. Now, those are not low carb diets, per se. Was there a common denominator there, or did these all end up at the bottom of the list for different reasons?
JW: I think that they ended up at the bottom of the list because they're restrictive And then that, of course, lowers the score on the ease of following the diet. That is one of the things that is scored—ease of following it. And as you said, the flexibility of those other diets makes them easier to follow. That gave them a higher score overall.
The other thing about it is when you're dropping out a bunch of foods, you have less nutrition. If you think about that, all those phytonutrients that we have in our plant foods or phytochemicals that help fight disease and protect us from cancer type 2 diabetes, heart disease, so forth—those are largely in the foods that are taken away in these various groups.
I think that fast weight loss is much more likely to be temporary weight loss. So that's generally not what I'm looking for in a diet plan.
ND: Some of the diets that ranked at the bottom of the list for overall diet actually ranked highest in sub-categories such as the one for fast weight loss. Now, frankly, I have always had a problem with that category. To me, it seems like a bit of an oxymoron because I think that fast weight loss is much more likely to be temporary weight loss. So that's generally not what I'm looking for in a diet plan. Do we need a different diet to lose weight than we do to stay healthy?
JW: Well, I don't think so. I think the fast weight loss diets really set us up to have two sets of unhealthful eating patterns. One is when we're losing weight and one is when we're gaining weight. And so I think it's not a good idea at all. But to answer the question in the survey, “Is this diet likely to lead to fast weight loss?” I had to say yes to keto and things like that. Because I think it is true—we see more rapid weight loss with very low carbohydrate diets than we do with other diet plans. But by the time you get out to year one and year two, there's really no difference anymore. And, of course, I prefer the diets that were rated best overall for weight loss because I don't care how long it takes somebody to lose weight. I just want them to lose it and keep it off.
ND: Jill, you specialize in diabetes education. Let's talk a little bit about that particular sub-category of the rankings because the diets were also looked at specifically in relation to diabetes. And I noticed that, in this case, the best diets for diabetes were actually very similar to the best diets overall. Why is there so much more concordance between diabetes health and overall health than there is between overall health and weight loss?
With diabetes prevention and management, we're looking for something that can be sustainable. We don't want to just prevent diabetes for 60 days—this is something we want to do for a lifetime.
JW: I think diabetes, particularly diabetes prevention, aligns so closely with overall health because diabetes prevention really has to be a healthy eating pattern. It should not be something like a very low carb, ketogenic diet. But I think that might be surprising to people because when they think diabetes prevention or diabetes management, they automatically think low carbohydrate. But with prevention and management we are looking for something that can be sustainable. Because we don't want to just prevent diabetes for 60 days. This is something that we want to do for a lifetime.
ND: We're hearing so much these days about plant-based diets being healthier for both people and the planet. And I think a lot of people looking at these rankings might be surprised that the vegan diet was actually halfway down the list at number 17 in terms of overall best diets. Although the vegetarian diet was higher at number nine. What do you think hurt the vegan diet in this particular rating process?
JW: Well, I can't speak for the other panelists, obviously, so I'm going on my own experience. "Ease of following" is probably one thing that made it lower in the rankings. But then also it's when we put an emphasis on avoiding foods. I would prefer if it were framed as healthy plant foods, but really the majority of people frame it as “I don't eat animal foods.” And when we look at diets of exclusion like that, the guidelines to eat health-boosting foods just aren't there sometimes. So, I think those are the two reasons. The ease of following it and then the lack of specific guidance for quality nutrition.
ND: I was actually wondering whether it had something to do with the fact that a vegan diet does exclude certain nutrients that we really can only easily get from animal foods. And you know, of course, it is possible to build a complete and healthy and balanced vegan diet, but you do have to work a little bit harder.
B12 is the only nutrient that you're not going to be able to get on a totally vegan diet.
JW: Exactly. B12 is the only nutrient that you're not going to be able to get on a totally vegan diet and you really do need it in a food supplement or fortified food, like a breakfast cereal.
ND: As you said, the panel did not confer with one another. Were there any rankings that differed significantly from your personal opinion?
JW: One that surprises me a little bit is the Nordic diet. That one ranked ninth overall, which tied with Ornish and vegetarian. But the concept of the new Nordic Diet is so similar to the Mediterranean style diet. It's basically, “eat wholesome foods that are local to you.” I'm surprised that it wasn't closer to the Mediterranean diet ranking.
I'm going to guess that it wasn't because we have a lot of research studies on the Mediterranean diet but there are fewer research studies published on the new Nordic diet, even though it is just so very similar in concept to the Mediterranean diet.
ND: Right. It's kind of a Mediterranean diet for people who live in colder climates.
JW: Exactly. That's exactly what it is. There are a couple of different things that don't show up in a Mediterranean diet: Use organic produce whenever possible and produce less waste. I think those are two things that are actually specific guidelines in the new Nordic diet that aren't in a Mediterranean diet, but the concept of the foods that you eat is so similar.
ND: Well, there is an enormous amount of research on the Mediterranean diet. It's gotta be one of the most studied diets in the history of nutrition research. And I once heard it said that was because researchers would much rather go to Greece on their travel grants and their research grants than Alaska or Norway!
JW: Norway is incredibly beautiful, just like Greece. But boy is it cold.
ND: So, in your view, now that we finally have this year's rankings, how can consumers best use this information? What's this actually good for?
There's more than one way to a healthy plate.
JW: I like to take the three top diets or the eight top diets, whatever, and then look at what they have in common and how you can make that part of your own personal path. I don't think that we need to pick up any diet book and think that that is the one path to health. There's more than one way to a healthy plate, and I think that this ranking speaks to that as well.
I say just look at the ones that speak to you and find the best parts of each one and move forward.
ND: And one of the convenient things about this report is that it does give you a pretty complete summary of the overall design and points of each diet in one centralized place.
You can take a look at US News & World Report's Best Diet Rankings for yourself. And to see more of Jill Weisenberger’s work, including her newest book on prediabetes, visit her website at jillweisenberger.com.