Between “slow-carb,” keto, and intermittent fasting (IF), there are so many buzzy diets these days that it’s almost hard to keep track. One of the latest eating styles to gain steam isn't exactly new, but has resurfaced recently with the rise of IF and more protein-based diets. It's called the Warrior Diet, and tbh, just the name itself is pretty intriguing, huh?
The Warrior Diet was originally created in the early 2000s by Ori Hofmekler and based on his own experiences with the diet, which are outlined in his book by the same name. The diet initially revolved around very small "underfeeding" meals of dairy, eggs, fruits, and vegetables for 20 hours of the day and a four-hour "overfeeding" window.
“Essentially, it was a very early version of intermittent fasting and said to mimic ancient warriors' lifestyle of training and battling throughout the day and consuming a majority of their calories during the evening in one massive feast,” explains Joel Totoro, RD, a sports dietitian and director of sports science at Thorne Research in Scottsdale, Arizona. “Hofmekler’s original plan also had exercise suggestions built into it.”
Okay, the Warrior Diet does sound interesting, albeit pretty dang intense. So is it actually healthy, safe and effective for weight loss? Here, experts break down everything you need to know about the Warrior Diet style of eating.
How exactly does the Warrior Diet work?
The diet has actually evolved from its original format since it was first created and the name was coined. More recently, the Warrior Diet has been interpreted as a strict 20-hour food fast and a four-hour fueling window, with various exercise requirements, says Totoro. This is also sometimes referred to simply as a 20:4 diet or 20:4 fasting.
The current version doesn’t have any food restrictions for the fueling period, but you’re not supposed to eat at all during the fasting period. While this might sound similar to the popular IF diet known as the 16:8 diet, in which you fast for 16 hours and eat during an eight-hour window, it's actually very different. First, it's much easier to fit your daily calorie needs into eight hours instead of four, and in the Warrior Diet, you fast during the majority of the day, which is much more challenging than fasting overnight and into a short portion of the day, like you would with the 16:8 diet.
What foods can you eat on the Warrior Diet and what should you avoid?
That depends which version of the diet you're following. The original Warrior Diet plan called for small meals of low-carbohydrate, naturally occurring foods such as eggs, dairy and nuts, paired with high-nutrient carbohydrate sources such as fruits and vegetables throughout the day, says Totoro. The daytime underfeeding period was followed by mass quantities of high-protein and high-fat foods paired with whole grain and whole-food carbohydrate sources during the overfeeding period at night. The more modern take on the Warrior Diet allows you to eat whatever you want during your eating window.
“While the original diet stressed nutritious and naturally occurring foods even during the ‘feast’ stages, the more modern, ‘free-for-all’ mentality can lead to overeating high-fat foods that are often lacking in nutrients,” says Totoro.
If you’re still intrigued enough to try it, he recommends easing into a fasting period a few days a week to assess how your body responds.
What are the health benefits of the Warrior Diet?
Because many people consume fewer calories than they normally would by only eating during a small window with this diet, this may lead to weight loss over time, Totoro says. However, there’s no scientific evidence at this point to support the Warrior Diet as an effective method for weight loss. And because the diet is so extreme, it may not be sustainable for many people.
Additionally, any evidence of potential health benefits related to the Warrior Diet is more based on the benefits of intermittent fasting in general, he says.
“With IF, there’s emerging evidence that for some people, shrinking the eating window may help with GI issues, blood sugar control, inflammation, and other conditions,” says Totoro. “But it's important to remember that everyone responds differently to fueling and activity and what works for some will not work for others.”
Are there any side effects of the Warrior Diet I should know about?
The Warrior Diet is restrictive and pretty extreme, which means it could lead to disordered eating habits for some people, says Amanda A. Kostro Miller, RD, a registered dietitian and advisory board member at Fitter Living.
“This diet promotes binge eating during the four-hour non-fasting period, which can lead to stomach distension, exacerbation of heartburn and many other GI symptoms,” she explains. “Some at-risk people may become obsessive about the binge session and may engage in harmful behaviors like purging to remedy feeling too full.”
Like any IF diet, you may also experience feelings of fatigue and hunger during the fasting period, which are signs the diet probably isn't a good fit for you.
Who should and shouldn't try the Warrior Diet?
This type of diet isn't sustainable for an extended period of time, so it's probably not a good idea for anyone, really. But its particularly dangerous for people who take medications that should be taken with food or are time-released, says Totoro. People with diabetes should also be extra cautious, since this type of diet could mess with your blood sugar.
Athletes who are training at a high or very competitive level should consult with their coaches and health care providers before trying this diet well, he adds.
Lastly, pregnant women, children, and people who have been diagnosed with eating disorders or dealt with disordered eating patterns in the past shouldn’t try this diet, says Kostro Miller.
The bottom line: The Warrior Diet is extremely restrictive and while it may lead to weight loss, it's likely not sustainable. Consult with a dietitian or health care provider before trying this diet.