If you are new to the concept of the Keto Diet the following article might help you to decide if it's the diet for you.
Is the keto diet just another synonym for hype? Or, is the keto diet actually good for weight loss? Let’s see what the science says…
Is the Keto Diet Good for Weight Loss? Here are 4 Separate Studies
Simply put, there’s no shortage of strong evidence that a keto diet works for weight loss. Even more, there’s good reason to believe it’s as effective—if not more so—than traditional weight-loss diets.
Let’s look at a randomized controlled trial published in the journal Endocrine. Researchers from Spain found obese participants following a keto diet for just two months lost nearly 30 pounds. During the same time, participants following a standard low-calorie diet lost just 10½ pounds.
After 12 months, 88% of the keto dieters had lost more than 10% of their initial starting weight. Plus, they maintained nearly 3 times more weight loss than the low-calorie group.
This is a key finding because research suggests many obesity-related conditions improve with modest weight loss (i.e., 5–10%). This can include high blood lipids, high blood pressure, diabetes, insulin resistance, sleep apnea, inflammation, cardiovascular disease risk, and more.
Take a look at another study published in The American Journal of Clinical Nutrition. Researchers found obese men following the ketogenic diet for 4 weeks lost nearly 14 pounds. These were 46% better results than a group eating a “moderate” carbohydrate diet.
One particularly compelling facet of this study was that calories were not actively restricted. In other words, the keto diet naturally lowered hunger and food intake. Worth mentioning, however, was that the keto diet used in this study was higher in protein (30% of calories) than the typical keto diet (15–20% of calories). And, it’s well-known that higher-protein diets are quite effective when it comes to appetite management.
In a study published in the journal Nutrition & Diabetes, 89 men and women, between 30 and 65 years old, with type 2 diabetes (T2D) were randomly assigned to a very-low-calorie ketogenic diet (VLCK) or a standard low-calorie diet based on the guidelines provided by the American Diabetes Association.
At the end of the 4-month trial, the keto diet group experienced significantly greater weight loss. They also lost more inches from their waistlines and experienced better improvements in blood glucose levels (HbA1c) and glycemic control compared to the standard dieting group.
The researchers concluded, “A VLCK diet is most effective in reducing body weight and improvement of glycemic control than a standard hypocaloric diet with safety and good tolerance for T2D patients.”
By the end of the study, 98% of the keto diet group experienced 5% weight loss while 85% of the group dropped 10% of their initial weight. In contrast, 50% and 17% of the standard low-calorie group lost 5% and 10% of their starting weight, respectively.
A couple important points about this study, however. During the “active phase” of the keto diet, participants ate mostly prepared meals. Their calories were also limited to just 600 – 800 per day. This active phase was maintained until the participants lost most of the weight-loss target, ideally 90%. On the other hand, the standard low-calorie diet simply restricted calories by 500 – 1,000 calories per day.
It’s quite possible this protocol tipped the figurative scale in favor of the keto diet. And while that may indeed be the case, this same very-low-calorie keto diet protocol has been shown to be a very useful and effective tool for weight loss while reducing belly fat, preserving muscle mass and strength, improving metabolic profile and markers of inflammation, reducing food and alcohol cravings, improving physical and sexual activity, reducing sleepiness, and enhancing overall quality of life.
Yet, perhaps most striking are the results from two separate systematic reviews. These arguably represent the most critical assessment on the topic.
In a meta-analysis of randomized controlled trials published in the British Journal of Nutrition, Brazilian researchers concluded, “Individuals assigned to a VLCKD [keto diet] achieve a greater weight loss than those assigned to a [conventional low-fat diet] in the long-term; hence, a VLCKD may be an alternative tool against obesity.”
In a meta-analysis published in The Lancet, a panel of researchers from Harvard Medical School concluded, “In weight loss trials, higher-fat weight loss interventions led to significantly greater weight loss than low-fat interventions.” 13 Full disclosure, unlike the above review study, not all the studies included in this analysis tested the keto diet.
What about when you add exercise to the equation? After all, it’s one of the most powerful tools for improving carbohydrate metabolism and metabolic health.
Several studies have shown that combining weightlifting with the ketogenic diet results in impressive changes in body composition (including significant reductions in body fat) when compared to a standard Western-style diet.
Now, you could certainly make the argument that a noteworthy body of the research is not comparing apples to apples. For example, comparing a very-low-calorie diet (regardless of macronutrient composition) to a low-calorie diet is bound to yield more favorable weight-loss results than the latter. Likewise, it’s not hard to believe that the keto diet is superior to the Standard American Diet.
Having said that, there’s no shortage of evidence demonstrating the effectiveness of the keto diet for weight loss. In other words, the keto diet is actually good for weight loss..
How Does the Keto Diet Work?
Be that as it may, it’s undeniable that the keto diet is effective for weight loss. That brings us back to the original question…how does it work?
According to Dr. Antonio Paoli, who’s an author of several published studies and review papers on the keto diet, a “simpler, perhaps more likely, explanation for improved weight loss is a possible appetite-suppressant action of ketosis.”
Cravings & Ketones
You see, the keto diet may flex its weight-loss muscle through elevated levels of ketone bodies, believed to have direct appetite-suppressant properties. In fact, ketosis is thought to be a key factor in the effectiveness of very-low-energy diets (VLED, = 800 calories/day). Of course, these represent the most intensive and single most effective dietary intervention for rapid initial weight loss and reducing obesity.
How Else Does the Keto Diet Promote Weight Loss?
From a practical standpoint, many (including even the staunchest keto advocates) trace the effectiveness (and benefits) back to RULES. You see, people like to be told what to do. They like guidelines and boundaries. They like some sort of standard up to which they can compare themselves. We want to know where we’re at. We want to know how we’re doing.
And the rules of keto do just that. Limit carbs to 30 grams per day (give or take). Simple as that. Of course, the ketogenic diet is far more complex than that. But from a figurative 1000-foot view, this is THE rule.
And when someone follows that rule, the menu of food options gets limited tremendously. You take a ton of ultra-processed, calorie-dense, highly-palatable “foods” off the table. And when you do that consistently over time, voilà! The keto diet can be tremendously effective for weight loss and lead to improvements in virtually all aspects of life and health.
Written by Tim Skwiat, MEd, CSCS, Pn2