If it feels like you're constantly bumping into people swearing by the keto diet, you're not mistaken - this diet does seem to be an effective fat-burning tool. That is the reason why it's not just your friends, but also celebrities like Vanessa Hudgens, Alicia Vikander, and Halle Berry who are now avid followers.

While people often prefer choosing diets that offer rapid weight loss, many of these diet & meal plans can result in health issues (remember Atkins?) or lead to rebound weight gain (hello, juice detox). As Hollywood shifted its focus towards sustainable eating habits and healthy lifestyles, one diet that rose to the top of popularity chart is Keto.

The ketogenic, or simply 'keto', diet is a high-fat, low-carb diet that promotes consumption of wholesome fats that the body can utilize for energy. This means food items like olives, nuts, fish, coconut oil, and avocados - all of which offer other health benefits as well, like enhancing brain health or improving skin texture.

The ultimate goal of a keto dieter is to achieve a state of ketosis, where their body begins to utilize stored fat for energy, explains NYC dietitian Keri Glassman.

Take Chad Johnson, for instance, a star of Bachelor in Paradise and a contestant from JoJo Fletcher's season of The Bachelorette. He has a trick up his sleeve for that toned TV appearance: “Before every show, I try to get on the keto diet. I usually have a diet rich in carbs and meat to build muscle. But a week before a show, I cut all carbs, go full keto, and I lose around five to seven pounds of fat within a week — or at least I seem to.” It was the premise of this high-fat, low-carb diet that initially lured him in.

Many other celebs believe the keto diet is hands-down the fastest way to shed pounds. Carbs are your body's energy, so on a keto diet, when you eliminate this energy source, your body is compelled to burn its own fat for fuel. So technically, we can say it's really the simplest way to lose weight.

Endowed with the perpetual charm of youth, Halle Berry, who also battles Type 1 diabetes, has always prioritized a wholesome, nutritious lifestyle. Interestingly, Berry had unknowingly embraced the keto diet long before it became a trendy wellness buzzword, her trainer, Peter Lee Thomas, revealed in late 2018.

He noticed her eating habits aligning with the then-burgeoning diet trend, saying, "It was quite surprising to see that you've been following the ketogenic diet even without realizing it!" Berry herself was equally surprised when she discovered that her food choices were already putting her in a state of ketosis.

Does the Keto Diet Really Work?

Diets low in carbohydrates, such as keto, do tend to result in some immediate weight loss, although some experts believe that keto diets don't have a significant edge over other popular or low carb diets or DIY diets. Moreover, they don't seem to boost athletic performance.

Also, your approach to keto diet can affect the balance of your lean body mass loss vis-a-vis fat loss. Normally, dieters aim to lose only fat, not lean body mass which includes muscle tissue. And like many other dietary trends, once people go off the diet, they often regain the weight they lost.

So what is the keto diet?

While the keto diet is known widely today as a weight loss strategy, its roots are steeped in medical history, having originally been developed to manage epilepsy. Physicians in the 1920s found that a diet low in carbohydrates caused the human body to use fat as the primary fuel source, rather than the commonly used glucose.

This switch in metabolic priority results in the body breaking down fats into fatty acids, which are further transformed into compounds known as ketones. These ketones serve as the body's main source of energy under these conditions- a metabolic state called ketosis.

This burns fat from a different mechanism, than most prescription drugs, like phentermine. For more information on mechanism & history of phentermine, checkout this piece on PRX.

Even though modern science has not entirely decoded why a body running on ketones experiences fewer seizures, the efficacy of this approach remains evident. However, Jo Ann Carson, a clinical nutrition professor at the University of Texas Southwest Medical Center and the American Heart Association's (AHA) Nutrition Committee chair, shares that the connection between ketosis and weight loss isn't completely understood.

Yet, now ketogenic diets remain a viable treatment option for those who see little improvement from medication.

The contemporary weight loss-centric keto diets are successors of earlier low-carb diet lifestyles such as the Atkins diet, which had its moment in the limelight in the early 2000s. These diets share a common theme – they place a higher emphasis on protein-rich meals and shun carbohydrates.

While there isn't a universal blueprint for a keto diet, the general guideline is to limit carbohydrate intake to less than 50 grams daily. To put it into perspective, an ounce of wheat bread carries about 16 grams of carbohydrates, according to the USDA.

Some experts also claim that ketosis curbs hunger and could impact hunger-regulating hormones like insulin. Additionally, consuming fats and proteins might lead to a sense of satiety, potentially reducing overall calorie consumption.

Keto Diet vs. Other Low Carb Diets

A comprehensive study, published in the Journal of the American Medical Association in 2014, investigated the effectiveness of various popular diets by analyzing data from 48 distinct diet experiments where participants were randomly assigned to follow a specific diet.

These diets ranged from low-carb options like Atkins, South Beach, and Zone diets, to low-fat ones such as the Ornish diet.

Portion-control strategies like those implemented by Jenny Craig and Weight Watchers were also included in the mix.

The research found that following any diet led to greater weight loss compared to not following a diet at all over a span of six months.

In another analysis conducted in April 2015 and published in the Annals of Internal Medicine, the Atkins diet was observed to induce more weight loss than strategies that simply emphasized portion control.

However, it's plausible that in most studies concerning this low-carb diet, registered dieticians played a vital role in guiding participants in their food choices. This kind of contrasts with the mainly self-directed approach taken by most people when they adopt these diets.

Speaking of keto diets, they have been confirmed to facilitate weight loss, yet their effectiveness is not necessarily superior when compared to other low-carb diets.

As Dr. Majumdar explains, the initial weight loss observed in the early stages of a keto diet can be because of the loss of water weight. This is because when carbohydrate stores in the body deplete, they also release their associated water molecules. While this might offer a good jumpstart to one's weight loss journey by rapidly moving the scale, the pace of weight loss is bound to slow down with time!