It was ranked #37 in the Best Diets Overall 2022, an annual list from U.S. News that looks at some of the most popular—and little known—diets around, including the Mediterranean Diet, the DASH Diet, and Intermittent Fasting.
Now in its 12th year, the Best Diets Overall list sees editors and reporters spend months reviewing medical journals, government reports and other resources to create what it calls "in-depth profiles" of each diet.
These profiles are then provided to a panel of 27 medical experts in diet, nutrition, obesity and food psychology to review.
Each diet is ranked in seven different categories, including its ability to produce short and long-term weight loss, how easy it is to follow, how safe it is, and its potential for preventing and managing both diabetes and heart disease.
Keto might be a popular diet with some celebs (Halle Berry, anyone?), but it scored low in every category except its ability to produce short-term weight loss, for which it scored a 3.7 out of 5. It's overall score? A measly 2.0.
"This diet is fundamentally at odds with everything we know about long-term health," one expert said.
Why do experts think Keto is ineffective for long-term weight loss?
The keto diet is a high-fat, low-carb diet designed to make your body enter a state called 'ketosis', where your body doesn't have enough carbohydrates to burn for energy and so instead begins to burn fats.
This diet is extremely hard to stick to, according to U.S. News' experts. And even those who do see results in the short-term struggle to keep the weight off long-term.
"People become very bored just eating fatty foods, fat and meant," one expert said. Another described it as "the hardest of the hard". (We guess that explains why modification diets such as the 'lazy keto' have cropped up.)
Nutritionally, the keto diet scored a 1.6 out of 5 for being "extremely incomplete", and it scored low in both managing or preventing diabetes (2.6/5) and heart disease (1.9/5).
"Any diet that recommends snacking on bacon can't be taken seriously as a health-promoting way to eat," one expert said.
Although this didn't factor into the Best Diets Overall rankings, the keto diet could also have a negative impact on your libido due to its recommendation of just 20g to 50g of carbohydrates per day.
“Some research suggests that a very low carbohydrate diet may cause a drop in thyroid function, which not only leads to fatigue and low mood, but may also negatively affect libido," nutritionist Lily Soutter said in 2018.
“Long-term, if our carbohydrate consumption is too low, it may also suppress our production of a hormone called leptin, which may ultimately interfere with our body’s abilities to regulate sex hormones."
What other diets should we avoid?
Technically speaking, keto didn't come dead last in the rankings. It was tied for last place at #37 with the Modified Keto Diet (a less drastic version of the keto diet), the Dukan Diet, and the Gut and Psychology Syndrome (GAPS) Diet.
The Dukan diet, which comes with four phrases and a complicated set of rules to what you can eat, was found to be too restrictive with too much protein and too little vegetables. The GAPS diet, which comes with a six-phase strict introductory detoxification process, was found to be severely restrictive with little medical evidence to back up its claims.
Which diet was the best overall?
It should come as no surprise that the Mediterranean Diet was ranked #1 overall, with experts finding it balanced, easy to follow, healthy, and good for both short-term and long-term weight loss (although it doesn't promise fast weight loss—and nor should it).
While some people fear a diet rich in fats like olive oil, olives, avocados and cheese will keep them fat, an increasing amount of research says the opposite is true. One such study of more than 32,000 Italians over 12 years found that the Mediterranean diet was associated with lower levels of weight gain and less of an increase in waist circumference.
The diet coming in at number two might not be a household name, but it's worth looking into. It's called the DASH diet, which stands for 'dietary approaches to stop hypertension', and encourages all the foods you know to be good (fruits, veggies, whole grains, lean protein and low-fat dairy) while discouraging the less health foods (anything high in saturated fat).
It also encourages small changes, such as adding one serving of fruit or vegetable to a meal, using herbs and spices to make food tastier without salt, and snacking on almonds or pecans instead of chips.
Which diets were best for fast weight-loss?
Although Keto promises to help you lose weight fast, it didn't even rank #1 for the best fast weight-loss diets (it was #4). That dubious honour goes to the Atkins diet, which largely cuts out carbs and scored very low for being healthy (2.0/5) and easy to follow (1.7/5).
The second top diet for fast weight loss was the meal-replacement Human Management Resources (HMR) Program, which replaces meals with shakes, while the third place diet went to the OPTAVIA diet, which replaces meals with shakes, bars, and soups.
We can't recommend following any of these diets; the key to health is a varied diet and habits that can be followed long-term, not drinking soups for the rest of your life.
Of course, don't just listen to us. If you want to change your eating habits in 2022, the best place to start isn't a celebrity or Instagram influencer. It's talking to your GP or a credited dietician.