A Dietitian's Guide to Fad Diets and Weight Loss

By Natalie Konieczny, RDN, Registered Dietitian Nutritionist—Virtua Nutrition

Often it seems there’s no end to the noisy parade of fad diets and their promises. These diets find us online, while we’re watching TV, or in social media through the excited claims of recently-converted friends and family members. They offer quick weight loss, a toxin flush, or maybe a smaller waistline in just days. And while some include all the components of healthy eating, many fall short. Through my practice, the women I’ve met lately are either trying or planning to try one of the following fad diets.

The Paleo Diet

The Paleo diet has been a big hit since it started growing in popularity in the early 2000s. Also known as the “stone age” or “caveman” diet, this regimen dictates that you only eat meat, seafood, nuts, seeds, and fruits, berries and vegetables that don’t contain starch. That means no dairy, cereal, bread, beans, starchy fruits or vegetables, or other refined food products. The idea is that you are eating what our primitive ancestors would have eaten, and nothing that wouldn’t have been available to them.

Does it work? Women who follow the Paleo diet are eliminating junk food and processed food, which is always, always a good thing. But, because the Paleo diet doesn’t specify portion sizes, extra care should be taken to eat regular meals and snacks to avoid binging on an “allowed” snack. When followed closely with good recipes, shopping lists, and cooking plans, you may find the Paleo diet can help you achieve the weight and fitness goals you’re pursuing.

Are there downsides? Getting rid of whole grains means eliminating the fiber and “good carbs” that help with brain function and energy levels throughout the day. While some women feel better on a Paleo diet, others may wither from the lack of B vitamins and other nutrients that are notoriously absent. 

Macro Counting (IIFYM)

“IIFYM” stands for If It Fits Your Macros, and macros refer to the 3 basic building blocks of our modern diet: carbs, fat, and protein. Macro counting is a very structured diet that requires tracking carbs, fat and protein after each meal throughout the day. Most who follow the diet use the help of a smartphone app that automatically does the calculations for you. The idea is for your overall daily diet to consist of 40% carbs, 30% fat, and 30% protein.

Does it work? It can, but that doesn’t mean it always does, or that it’s a healthy way to lose weight. Many women enjoy the flexibility that this plan allows. It doesn’t eliminate particular foods or food groups like so many popular diets today. But, that also can translate into temptation to revert to unhealthy food choices. However, I have seen patients who’ve had good weight-loss results by healthfully following the plan. 

Are there downsides? With a “no-restrictions” diet like macro counting, it doesn’t matter where your calories or macros come from. You can eat a candy bar as long as it “fits your macros” for the day. Healthy eating is not explicitly promoted with this diet, which is a big red flag for me. The constant tracking also can be time-consuming.

The Military Diet

Despite what its name might suggest, the military diet has no direct link to any military branch. Rather, it’s an eating plan that mimics the intense rigor associated with our armed forces. Dieters follow a strict, low-calorie eating plan for 3 days. On the other 4 days of the week, you eat what you like, and then start again. Proponents of the diet claim it can help you lose up to 10 pounds in a week. 

Does it work? The quick and dramatic calorie reduction might make it a little easier to zip up your dress for a party this weekend. But, I haven’t seen evidence that the military diet helps with weight loss over the long term. Even if you follow the diet and lose 10 pounds that quickly, you’re most likely going to gain it back quickly.

Are there downsides? Strict and drastic dieting can negatively affect your metabolism. On the restrictive calorie days, you’re not giving your body the proper nutrition it needs to function at its best. I also worry that weight-loss plans like the military diet can promote unhealthy eating habits like binging on “off” days.

The Juice Cleanse

We’ve all heard of juice cleanses, whether it’s from a co-worker over coffee or online from celebrities like Gwyneth Paltrow or Beyoncé. Juice cleanses have exploded in popularity over the past decade, and web-based and brick and mortar juice shops are doing a brisk business. The cleanses, which are usually 1-, 3- or 5-day plans, specify a unique juice or combination of juices for each day. They often tout distinct health benefits for each day’s ingredients and sometimes promise quick weight loss or the “elimination of toxins.” 

Does it work? Avoiding food is never a good approach to weight loss. You may lose some weight right away, but expect to feel deprived, because you will be. When a fruit or vegetable is juiced, all of the valuable and nutrient-rich pulp and roughage—the parts that make you feel full—are wasted. As for toxins, our livers and kidneys are perfectly capable of removing toxins with or without juice. 

Are there downsides? Juice cleanses may be cost-prohibitive for some. Pre-made cleanses that ship to your door come with a hefty price tag—anywhere from $40-90 per day, and sometimes more. For the price of a single day on some plans, you could buy a quality juicer and mimic a popular plan with your own ingredients. But, keep in mind that not all ingredients are wallet-friendly—a whole head of broccoli, for example, gives you about a tablespoon of juice.

Get the Weight Loss Help You Need

Virtua registered dietitians can help you create a healthy eating plan that helps you lose weight while maintaining the flexibility you need. Call 1-888-VIRTUA-3 for an appointment. 

Updated September 28, 2020