The Keto Diet and Intermittent Fasting are Effective for Weight Loss
January is “National Dieting Month” in the United States, and the spotlight is on the Keto Diet and IF, aka intermitent fasting.
They are the latest dietary trends and the Big Q’s are: Do they actually work? Are they sustainable?
Dieting isn’t a modern phenomenon. In the 1960’sss the cabbage soup diet was popular for weight loss, and Weight Watchers began around that time. The early 1970’s saw the grapefruit diet, followed by the Sleeping Beauty plan, which Elvis Presley was reportedly a fan of. If you are sleeping then you are not eating.
The paleo diet can be traced back to the 1980’s, while the Atkins diet, started in the 1990’s regained popularity when Kim Kardashian credited it for helping her shed extra pounds after childbirth.
Then in Y 2011, it was as if Americans woke up and collectively agreed to start throwing coconut oil into everything. This was soon followed by juice cleanses and diet pills.
The the favorite diets of today are the ketogenic (keto) diet and intermittent fasting (IF).
The Keto diet is a high-fat, low-carb meal plan where people aim to consume only about 5 to 10% of their total calories as carbs. It it is made up of mostly fats, and moderate protein.
The idea is that a sharp reduction in carbs will put the body into a metabolic state called ketosis where the body begins to burn fat, instead of sugar, for fuel. The liver also produces ketones from fat, which can supply energy throughout the body, especially for the brain.
IF is an eating pattern that cycles between periods of fasting, with either no food or significant calorie reduction, and periods of unrestricted eating. Popular versions of IF include the 5:2 diet, which allows for normal eating for 2 days, and a low-calorie diet of about 500 calories per day on 2 non-consecutive days of the week. Another version of IF is the 16/8 diet, where 1 fasts for 16 hours each day, and eats only within an 8-hour nutritional window.
We asked Dr. Lim Yen Peng, Do they work?
Dr. Lim is the senior principal dietitian and head of
the Nutrition and Dietetics department at Singapore’s Tan Tock Seng Hospital
According to Dr Lim, though small-scale studies have shown benefits of the Keto diet and IF, the long-term effects of these regimes remains to be seen. While research has shown that the Keto diet may bring about short-term benefits such as weight loss and an improvement in blood sugar and cholesterol over 12 wks or less, it is challenging for individuals to maintain this diet due to the disproportionate distribution of fat and carbs.
Similarly, the long-standing impact of IF is unclear, says Dr Lim. “As people are more mindful of their food choices and are keen to make dietary changes, that is a positive sign as it means that they are motivated and empowered to make changes to their lifestyle. Subconsciously, they may have also cut down on their overall intake and consume less calories as a result of being on these diets, even though these diets do not claim to be calorie-restrictive.”
“They will then experience some initial weight loss, which provides a positive reinforcement that these diets are effective for them.”
Nonetheless, she cautions that the applicability of these diets to people with various health conditions is ambiguous, especially among those with liver or kidney problems. “People with Type 1 diabetes, those who are pregnant, elderly, or adolescent, are not suitable. Some other side-effects of long-term ketogenic diet include high uric acid level in blood, osteoporosis, and kidney stones,” she says.
Another issue with the Keto diet is that it does not specify the proportion of unsaturated to saturated fats in meals. As such, it is possible for individuals to consume excessive high-saturated fats that can adversely affect cardiovascular health, Dr Lim says.
Separately, those taking medication for diabetes, pregnant women, people with eating disorders and children or adolescents should not consider trying IF, Dr Lim explains. She adds that both diets are generally not recommended to people who are keen to lose weight, as they may be restrictive and not sustainable.
As she puts it: “Individuals may experience uncomfortable feelings that can affect their mood, fatigue, headaches. If it is not well-planned, those on Keto diet may develop certain nutrient deficiencies if a wide variety of food is not included. For IF, it is still important for the food choices to be healthy and nutritious during non-fasting periods.”
On that note.
Dr. Lim highlights that it is important for people to appreciate that in order to achieve long-term weight loss, one will need to couple healthy diet choices with increased physical activity, while enjoying a variety of food in suitable portions. For sustained weight loss, 1 will need to adopt “lifestyle and behavioral changes” that can be adhered to in the long run, instead of seeking quick-fix solutions.
Eat healthy, Be healthy, Live lively