Evaluating Popular Diets

— Written By and last updated by
en Español / em Português

El inglés es el idioma de control de esta página. En la medida en que haya algún conflicto entre la traducción al inglés y la traducción, el inglés prevalece.

Al hacer clic en el enlace de traducción se activa un servicio de traducción gratuito para convertir la página al español. Al igual que con cualquier traducción por Internet, la conversión no es sensible al contexto y puede que no traduzca el texto en su significado original. NC State Extension no garantiza la exactitud del texto traducido. Por favor, tenga en cuenta que algunas aplicaciones y/o servicios pueden no funcionar como se espera cuando se traducen.


Inglês é o idioma de controle desta página. Na medida que haja algum conflito entre o texto original em Inglês e a tradução, o Inglês prevalece.

Ao clicar no link de tradução, um serviço gratuito de tradução será ativado para converter a página para o Português. Como em qualquer tradução pela internet, a conversão não é sensivel ao contexto e pode não ocorrer a tradução para o significado orginal. O serviço de Extensão da Carolina do Norte (NC State Extension) não garante a exatidão do texto traduzido. Por favor, observe que algumas funções ou serviços podem não funcionar como esperado após a tradução.


English is the controlling language of this page. To the extent there is any conflict between the English text and the translation, English controls.

Clicking on the translation link activates a free translation service to convert the page to Spanish. As with any Internet translation, the conversion is not context-sensitive and may not translate the text to its original meaning. NC State Extension does not guarantee the accuracy of the translated text. Please note that some applications and/or services may not function as expected when translated.

Collapse ▲

There are so many diets floating around the internet and on social media, it’s really hard to know what works and what doesn’t and also what’s really healthy. Kelly Nordby, RDN, LDN addresses this topic on the Eat Smart, Move More, Weigh Less blog.

Kelly Nordby 

Kelly Nordby, MPH, RDN, LDN serves as the Eat Smart, Move More, Weigh Less and Eat Smart, Move More, Prevent Diabetes Coordinator. She has a Master’s of Public Health in Human Nutrition. She is also a Master Trainer Select and trained Lifestyle Coach for the National Diabetes Prevention Program. Eat Smart, Move More, Weigh Less is an evidence-based weight management program and Eat Smart, Move More, Prevent Diabetes program, a CDC-recognized Diabetes Prevention Program. Both programs are delivered online in real-time in an interactive format. 

As a dietitian, she has two questions that she uses when evaluating a diet to determine if it is based on science and if she could recommend it to her clients. These questions relate to allowing or limiting different foods.

The foods she wants to see allowed are what she calls “super foods” such as fruits and vegetables, nuts and seeds, whole grains and plant-based oils (primarily olive oil.)

The foods she wants to see limited are sugars, red meat, saturated fats and highly processed foods.

Several years ago, she analyzed eight popular diets and recently updated her recommendations to reflect recent research. It’s interesting to note that the only recommendation she changed was for Intermittent Fasting. She still does not recommend this practice but added that it “may be beneficial for some to reduce nighttime snacking.” She says there isn’t enough evidence yet to show that intermittent fasting is effective in humans. It’s also hard to sustain a fasting diet because it’s difficult to follow and may not be compatible with family and social life.

Here are her thoughts on some of the other more popular diets:


DASH diet (Dietary Approaches to Stop Hypertension) — This is an eating plan that requires no special foods. It recommends eating vegetables, fruits and whole grains. It includes fat-free and low-fat dairy products, fish, poultry, beans, nuts and vegetable oils. It limits foods that are high in saturated fat and sugar-sweetened beverages and sweets. It was developed by the national Heart, Lung and Blood Institute. She does RECOMMEND this diet.


This diet allows fruits and vegetables, nuts and seeds and plant-based oils. It limits added sugars and processed foods. Her concerns are that it excludes whole grains, legumes. The Paleo diet also does not limit red meat and saturated fat. She does NOT RECOMMEND this diet.

Mediterranean Diet

This is not really a diet but a healthy eating plan. It is plant-based and incorporates the traditional flavors, foods and cooking methods of the Mediterranean region. This eating plan allows for fruits and vegetables, nuts and seeds and whole grains. It limits processed foods, added sugars and simple carbohydrates. She does RECOMMEND this diet.

Blood Type Diet

The idea of this diet is that you eat based on your blood type. The claims are that the foods you eat react chemically with your blood type and when you follow a diet designed for your blood type your body will digest food for efficiently. This diet does allow fruits and vegetables and generally allows nuts and seeds and whole grains. It also limits added sugars, simple carbohydrates and processed foods. She does NOT RECOMMEND it because it could unnecessarily limit some healthy foods like nuts and seeds and some whole grains for some blood types.

Ketogenic Diet

Allows for non-starchy vegetables, nuts, plant-based oils and some fruit such as avocado and berries. It limits added sugars and processed foods. Her concerns are that it limits most fruit and excludes whole grains and legumes. It also excludes root vegetables like carrots, parsnips, potatoes and sweet potatoes. She does NOT RECOMMEND this diet because it does not limit red meat or saturated fats.

If you’d like to see her complete list of and review of popular diets you can find it at the Eat Smart Move More Weigh Less blog.

You can also find information on the ESMM programs at that site. Both are developed by professionals from NC State and the NC Division of Public Health.

Syracuse is a Family and Consumer Science team member and can be reached at N.C. Cooperative Extension, Brunswick County Center 910-253-2610 or by email at Cheryle_Syracuse@ncsu.edu