A balanced diet essentially consists of carbohydrates, proteins, fats, vitamins, minerals and water, with carbohydrates being the primary source of calories, followed by proteins and fats.
The human body’s fuel is glucose, the simplest form of sugar derived from carbohydrates or carbs. When in need of energy, the body turns to glucose stored in it.
But when the body does not have enough carbs to burn, it starts burning fats and breaks down into ketones or acidic chemicals. The process is called ketosis.
Keto or ketogenic diet, a popular weight loss programme, is based on this principle. The diet is very low in carbs, moderately low in protein, and very high in fat content, which could be up to 70-80 per cent of one’s diet.
The role of ketones
When glucose is not available, bile juice in the liver breaks down the fat that one consumes, as well as the fat stored in the body, into ketones. Even when one consumes a high-carb diet, one’s liver still regularly forms ketones and the process is called ketogenesis.
“After one to two days of low carbohydrate intake, the body’s glucose reserve runs out. Your liver can produce some glucose through a process called gluconeogenesis from amino acids, glycerol, and lactate, but not enough to satisfy your brain’s needs as it requires a steady source of fuel,” explains Chennai-based clinical nutritionist Anusha Santhanakrishnan. In such a condition, ketosis can give an additional source of energy especially to the brain, she adds.
Typically, ketones are formed after fasting, exercising for long hours or when one is on a low-carb diet. “When you sleep at night, the process of ketosis [slows.] But when your glucose levels and insulin in blood drop, as they do when you are on a low-carbohydrate diet, your liver increases the production of ketones to fuel your brain and body,” Santhanakrishnan adds.
Low levels of ketones are always present in blood and are not a cause for concern. But high levels of ketones should not be ignored. When ketones build up in blood, they can turn it acidic and lead to diabetic ketoacidosis.
How ketosis works
When the body is going through ketosis, one of the early signs is that one does not feel hungry as frequently as before. “It is not unexpected that ketogenic diets have been demonstrated to either outperform or be similar to other weight loss diets because they suppress appetite, lower insulin levels and promote fat burning,” says Abarna Mathivanan, a dietitian based in Delhi.
In addition to becoming an energy source, ketones help to lower oxidative stress and inflammation, two factors that contribute to many chronic conditions. In the case of people with Type 2 diabetes and conditions of prediabetes, ketosis can help to stabilise blood sugar levels and increase insulin sensitivity. A study published in Cell Metabolism in 2016 showed that ketosis improves endurance during high-intensity exercises.
“Ketosis [when maintained] with the modified Atkins diet is successful in managing epilepsy in both children and adults who do not react to anti-seizure medication,” points out Mathivanan. The modified Atkins diet, she says, is less restrictive than the traditional ketogenic diet.
Ketosis may be helpful in managing a variety of other conditions, including lowering the frequency and severity of migraine headaches, PCOS or polycystic ovarian syndrome, and delaying the progression of Alzheimer’s disease, she adds.
Diet and fasting help
Nutritional ketosis, which is essentially for weight loss, can be achieved in a number of safe and efficient ways. One of them is by sticking to a diet of less than 50 grams of carbs a day. Intermittent fasting or skipping meals for 16 to 18 hours could speed up the process
Jaya Sharma, a nutritionist based in Jaipur, says healthy individuals (who do not have diabetes and are not pregnant) will typically develop ketosis three to four days after they begin a diet of less than 50g of carbs per day. That is equivalent to two small bananas, a cup of low-fat fruit yogurt, or three slices of toast. Fasting can also kickstart ketosis.
“When you start out, increasing your intake of calories from fat and protein might help you to shift to burning fat while feeling less hungry. However, be mindful of the calories and the quality of fats you consume. Avoid eating fried foods and replace that with healthy fats such as MUFA from virgin olive oil, PUFA and MUFA from nuts, fish and whole milk,” advises Sharma.
Ketosis can be confirmed from one’s breath, or with blood or urine tests. However, the reliability and frequency of lab tests vary substantially and should be done with medical advice.