"There's No Reason to Cut Out Important Nutrients": An Expert Weighs in On Slow-Carb Diets

Introduced for the first time back in 2010 by author and lifestyle guru Tim Ferriss, the slow-carb diet is witnessing a resurgence. Right now, on TikTok, videos related to the term “slow carb diet transformation” have more than 28 million views, with many users claiming that the diet helped them to lose significant amounts of weight in a short amount of time. But is the slow-carb diet really that healthy? We spoke to Stephanie Wells, MS, RD, ACSM-CPT of Thyme to Go Vegan Nutrition Services to find out more.

What is the slow-carb diet?

In his book The 4-Hour Body, Ferriss lays out a method that he believes can help with fat loss, blood sugar stabilization, and energy. The diet in question prioritizes the consumption of lean protein, healthy fats, and, of course, “slow carbs.”

“‘Slow carbs’ isn’t a true scientific term, but it’s usually used to describe whole, unprocessed sources of carbohydrates rich in dietary fiber,” Wells explains. So these are foods like beans, legumes, and whole grains. Refined carbohydrates (or “fast carbs”) are not permitted on the slow-carb diet. Think, white bread, crackers, and white rice, for example.

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As well as whole carbohydrates, the diet is particularly high in animal protein. It recommends that people choose foods like chicken, beef, eggs, pork, fish, and whey powder to hit their protein intake for the day. The slow-carb diet also allows for a small group of vegetables, including spinach, asparagus, peas, and green beans, as well as fats, like nuts and olive oil, and herbs and spices. Dairy and drinks other than calorie-free or low-calorie options, like water and black coffee, are not advised.

The theory behind this approach is that limiting food choices to only a handful of options will help people stick to the diet for six days out of the week. The seventh day is a “go nuts day,” as Wells calls it. “You’re encouraged to eat all foods in any quantity, regardless of how healthy they are,” she explains. “It’s basically, a cheat day.”

Is the slow-carb diet healthy?

The vast majority of people who follow the slow-carb diet do so to lose weight, and in the short term, it’ll likely work for most people, says Wells. But that doesn’t necessarily mean it’s healthy. The slow-carb diet does allow for nutritious foods, like some vegetables, beans, and legumes, but it also restricts other nutrient-dense options, like fruits and starchy vegetables (this includes foods like sweet potatoes and butternut squash, for example). 

“While replacing refined carbs with whole, minimally processed carbohydrates is an effective way to get more fiber, vitamins, and minerals, the Slow-Carb Diet takes this idea and turns it into an ultra-restrictive fad diet,” says Wells.

Wells also points out that the slow-carb approach encourages a binge-and-restrict approach to food. This may help people to lose weight in the short term, but it doesn’t help to build long-term healthy eating habits. In fact, research suggests that overly restrictive diets don’t work in the long term, with most people who follow rigid rules around food gaining weight back in the future.

“Whole grains, fruits, and starchy vegetables contain important nutrients like B vitamins, vitamin C, potassium, and resistant starch and help reduce the risk of many chronic diseases, so there’s no reason to cut them out.”—Stephanie Wells, MS, RD, ACSM-CPT

This is largely because diets are often too restrictive to be sustainable. They frequently don’t allow for fun foods or treats, and this also has a knock-on effect on mental health. “For long-lasting weight loss, it’s important to make changes that you enjoy and can sustain over a lifetime,” says Wells. “The Slow-Carb Diet’s emphasis on a restrict-binge cycle is also a bad idea for mental health and does nothing to encourage a healthy relationship with food.”

Can you lose weight without a restrictive diet?

People who want to eat healthier, and potentially lose weight, should incorporate “a variety of whole fiber-rich carbohydrates into a well-balanced diet,” notes Wells.

Research suggests that a predominantly whole-food, plant-based diet, for example, which leaves room for many different foods, including treats and shelf-staple options, is one of the healthiest ways to eat. In fact, it is associated with a lower risk of heart disease, type 2 diabetes, and certain types of cancer.

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The Mediterranean approach to eating, which also emphasizes vegetables and makes room for foods like wine and pasta, has also been named the healthiest diet by the U.S. News and World Report multiple times. 

“The Mediterranean diet focuses on diet quality rather than a single nutrient or food group,” notes the publication after releasing its 2024 report on healthy diets. “Numerous studies have shown that it reduces the risk of chronic health conditions, including heart disease and type 2 diabetes while promoting longevity and improving quality of life.”

If weight loss is your goal, both diets are also associated with fat loss. This is because both approaches prioritize whole foods, which are nutrient-dense but often lower in calories than processed options.

To find out more about how to follow a balanced, whole-food diet, follow our guide here. And you can also find an abundance of recipes, for everything from desserts to snacks to tasty dinners, lunches, and breakfasts, here.

Charlotte is a writer and editor based in sunny Southsea on England’s southern coast.