January 2018 Issue

Ask the Expert: Keeping Up With Fad Diets
By Toby Amidor, MS, RD, CDN
Today's Dietitian
Vol. 20, No. 1, P. 10

Q: Heading into the new year, what are some of the fad diets that are most popular?

A: While fad diets come and go, with some lingering longer than others, it's important for dietetics professionals to stay abreast of the ones clients are trying or thinking about trying. The following are four diets that are at their peak of popularity heading into 2018.

Alkaline Diet
The theory behind the alkaline diet is that acid-producing foods will lead to a metabolic imbalance. The diet claims that eating more alkaline-forming foods and fewer acid-forming foods will help reduce inflammation and increase resistance to disease. Accordingly, the diet promotes eating 80% alkaline-forming foods (such as fruits and vegetables) and 20% acid-forming foods (such as fish, poultry, meats, dairy, caffeine, sugar, and salt).

Quick debunk: The biochemical processes that the human body undergoes are complex; however, under normal conditions, the cells and blood maintain the body's neutral pH.

Macros Diet
Also called Flexible Dieting and If It Fits Your Macros (or IIFYM), this plan has become popular among CrossFitters, models, and body builders and has gained traction through social media enthusiasts. The plan promises to minimize hunger, balance energy levels, and curb sugar cravings. The theory behind it is to feed the body "ideal nutrition" (ie, individualized ranges of macronutrients) to make it more efficient. Dieters start with target macros, eg, 50% carbohydrates and 25% each of protein and fat, and can adjust ratios based on body type, goals, and activity level. To keep track of macros, dieters must count calories using spreadsheets or smartphone apps. Treats such as doughnuts are allowed, as long as they fit into the macro ratio.

Quick debunk: Tracking food intake can help dieters lose weight, but this plan offers no weight loss advantage over other calorie-counting plans. Furthermore, most online sites have inaccurate nutrition information and encourage users to sign up for a pricey meal plan ($749 for a 90-day coach-supported weight loss plan).1

This elimination diet promotes fresh foods while eliminating anything processed (and even some whole foods in their unprocessed forms), including all grains, dairy, soy, legumes, sugar, certain preservatives, and artificial sweeteners. According to Melissa and Dallas Hartwig, authors of the popular book The Whole30: The 30-Day Guide to Total Health and Food Freedom, the list of foods to be eliminated have been linked to a variety of health problems including hormonal imbalances, systemic inflammation, and gut issues. By strictly following the Whole30 plan for 30 days, dieters are promised improved digestion, skin health, metabolism, and fitness, and an overall sense of well-being. The daily eating plan consists of three meals with modest portions of protein, fruits, vegetables, nuts, seeds, and fats from oils, butter, coconut, and olives. Snacking is frowned upon, unless it's properly planned before or after a workout. Once the 30 days are completed, the eliminated foods can be slowly added back into the diet depending on how the body responds to reintroduction.

Quick debunk: It's a red flag for any diet to eliminate numerous food groups, including grains, dairy, and legumes.

Blood Type Diet
This diet was created by naturopathic physician Peter D'Adamo, ND, MIFHI, under the premise that blood type determines which foods one should eat and how he or she should exercise to improve digestion, lose weight, and feel good. For example, type As do best on a vegetarian diet and practicing yoga and meditation, while type Os see success following an animal-based diet with regular aerobic exercise such as running.

Quick debunk: A 2014 study published in PLOS One examined more than 1,450 healthy adults who followed this diet. Although some of the diets had positive effects on factors such as BMI and triglycerides, these were independent of the participant's blood type.2

— Toby Amidor, MS, RD, CDN, is founder of Toby Amidor Nutrition (http://tobyamidornutrition.com) and the author of the cookbook The Greek Yogurt Kitchen: More Than 130 Delicious, Healthy Recipes for Every Meal of the Day and The Healthy Meal Prep Cookbook. She's a nutrition expert for FoodNetwork.com and a contributor to US News Eat + Run and MensFitness.com.

1. Our programs. If It Fits Your Macros website. https://www.iifym.com/our-programs/. Accessed November 7, 2017.

2. Wang J, García-Bailo B, Nielsen DE, El-Sohemy A. ABO genotype, 'blood-type' diet and cardiometabolic risk factors. PLoS One. 2014;9(1):e84749.