I recently saw a 23-year-old obese (weight 92 kg, BMI 33 kg/m2) girl. She was smiling but looked unsettled. She told me, “Doc, I have been on a Keto diet for the last two months and have lost 4 kg of weight. Yet I feel feverish, fatigued, dizzy, have plenty of cramps, insomnia, my breath smells so bad. And I have trouble eating all that high fat-oil laced diet daily.” So, she did lose weight but suffered from some long-lasting side effects in the bargain.
What is a ketogenic diet?
The story of Keto diets started with Atkins diets, which rapidly gained popularity. “Dr Atkins New Diet Revolution: The High Calorie Way to Stay Thin Forever” has sold 12 million copies and remains a bestseller till this day. Predominantly non-vegetarian Western populations loved this diet (Breakfast: Greasy ham, bacon and eggs; lunch, steak with plenty of cheese; and dinner, fish, crab, and chicken cooked in a whole lot of butter). This diet leads to rapid weight loss in many individuals. Low carbs (less than 30 gm per day, equivalent to about one-and-a-half rotis) lead the body to find alternate routes to energy generation from acidic ketone bodies (hence the name ketogenic diet). These ketone bodies provide energy in an efficient manner and suppress appetite. Since then, several similar diets have emerged due to two reasons. First, to consistently consume very low carb, high fat and protein daily is difficult, hence the quantity of carbs per day has been increased in the modified diets. Second, it is not possible for vegetarians to eat a diet designed by Atkins, hence, ghee, coconut oil etc have been added in surplus.
What are pluses and minuses?
There are several plus points for this diet. Rapid weight loss can be achieved, sometimes more than that seen in usual calorie restrictive diets. In patients with diabetes, blood sugar levels and sensitivity to insulin improve and the need for anti-diabetic medications decreases. The diet may help patients with polycystic ovaries as well by improving their metabolic environment. Interestingly, robust evidence indicates that these diets have been known to decrease seizures in children resistant to high dose medications. Further, there is persuasive evidence for effects of these diets on acne. Although tried, there are no clear benefits in cancers, Parkinson’s disease and Alzheimer’s disease.
But many scientists are not ready to accept this diet because of uncertainty regarding benefits and harms. There are several known adverse effects and some not known or proven. While short term weight loss is slightly superior to conventional weight loss diets, long-term results are not yet known. In animals, this diet is known to increase density of fat in the liver (worsen fatty liver), which remains a concern in humans, short of good data. Recent reports show an increase in bad LDL cholesterol with these diets, which could adversely impact heart health. Finally, no good studies are available concerning Indians, who have bad liver (plenty of fatty livers) and LDL cholesterol (blood is full of fats, which could lead to dense deposition in the arteries that may cause blockages).
Who should not follow ketogenic diets?
First, these diets are a no-no for patients with heart failure and heart rhythm irregularities. Second, avoid such diets in patients with disturbed functions of kidney and liver, and history of pancreatic inflammation (pancreatitis). For patients with diabetes, extra precautions are needed when using these diets. Those who have Type 1 diabetes or have pregnancy with diabetes should not try this out at all. Many diabetic patients, who are on SGLT2 Inhibitors (Empagliflozin, Dapagliflozin and Canagliflozin) should be careful since Keto diets and these drugs would have additive effects on ketogenesis, which could reach dangerous levels. Finally, those who are on blood thinner (Vit K-dependent anticoagulation) should avoid Keto diets.
Is it worth short-term gains?
It looks like Keto diets are not a panacea for weight loss, only somewhat better than conventional weight loss diets in the short-term. So low carbohydrate Ketogenic diets are a reasonable option for rapid weight loss among young obese individuals with no organ dysfunction. This should be tried for three to six months under supervision of nutritionists and physicians. Cholesterol and liver profile should be done to check for any extreme responses. Similarly, in obese young and recently detected patient with diabetes (not on SGLT2i), this diet is a reasonable option to check surge of sugars or even for reversal of diabetes. Finally, the effect of very low carb Ketogenic diets on longevity is unknown, and one study suggests these are not favourable.
(The author is a Padma Shree Awardee and author of the book “Diabetes with Delight”)