INTERMITTENT FASTING EVERYTHING YOU NEED TO KNOW
Intermittent fasting has fast become one of the world’s most popular methods of losing weight, but how exactly does it work, and is it safe?
Everyone in diet and fitness circles is talking about intermittent fasting. While the reason for its sudden popularity can be attributed to its strong association with international celebrities such as Jennifer Lopez, Beyoncé, Hugh Jackman and many others, Dr Nandipha Ndhlovu, a general practitioner with a special interest in aesthetic medicine, has another suggestion.
“The notion that some form of fasting might have health benefits is nothing new, but [intermittent fasting] has gained currency in recent decades because of research showing that calorie restriction can extend the lifespans of many life forms such as bacteria, mice, rats and monkeys,” Dr Ndhlovu explains. “This has not been proven in humans for obvious reasons – ethics!” she exclaims.
As the name suggests, intermittent fasting is an eating pattern that cycles between fasting and eating, without necessarily specifying what types of food you should eat on non-fasting days.
While there are different methods of intermittent fasting, the general idea is that you eat as normal on some days of the week, and then on other days you reduce your calorie intake quite considerably, aided by fasting.
“On a fasting day, a person’s intake is often limited to non-caloric fluids such as water, tea, coffee (with low-fat milk) or it may allow a very restricted amount of daily calories,” Mbali Mapholi, dietician and spokesperson for the Association for Dietetics in South Africa, explains. It’s recommended that all liquids must have a caloric intake of less than 50 kJ, which means that no alcohol is allowed.
DIFFERENT TYPES OF IF METHODS
There are a variety of methods that you can choose from. Dr Ndhlovu takes us through the three most common ones. ALTERNATE-DAY FASTING
This diet is also known as the 24-hour diet. The dieter eats unrestricted for one day and doesn’t eat at all the next day and so on.
This popular method has been endorsed by celebrities such as Jimmy Kimmel. “The routine is also known as the 5:2 diet, in which the dieter eats normally for five days a week and greatly restrict food intake two days a week. The caloric intake during these two days must not exceed 500-600 kJ for females, and 1 000 kJ for males,” Dr Ndhlovu explains. TIME-RESTRICTED FASTING
Also known as the 16:8 diet, this type dictates that the dieter must eat all meals within an 8-hour window and fast for 16-hours. For example, you’d only eat between 12-8pm and fast for the remaining 16-hours.
DOES IF MELT AWAY FAT AND INCREASE LIFESPAN?
Dietary restrictions such as those seen in intermittent fasting can manipulate mitochondrial networks in cells, Mapholi explains, adding that recent research has suggested that this manipulation of cells does have the potential to increase your lifespan, but the research is not absolute.
“In terms of weight loss, current research indicates that intermittent fasting and continuous calorie restriction seem to produce weight loss results, so there may be an argument for considering it as a weight loss method,” Mapholi says with a bit of hesitation.
“However, if it was to be considered an option, it’d be important to highlight the potential risks related to fasting and low-calorie intakes, as well as the consideration of the overall limited evidence base and uncertainty about the long-term outcomes of intermittent fasting,” she adds.
PROS AND CONS
While there have been numerous studies that have suggested that, over and above the weight loss benefit, intermittent fasting can improve metabolic health and reduce a person’s chances of developing type 2 diabetes and heart disease – again, the research isn’t without limitations. Mapholi cautions that we shouldn’t necessarily accept all of these as fact.
“Many of these studies were performed on rodents and most of them were not done over a significantly long enough period of time,” Mapholi explains.
“Intermittent fasting, if unsupervised by a medical professional depending on a person’s age, medical history and lifestyle, can be detrimental to health by increasing insulin resistance while decreasing important detoxifying enzyme functions, muscle mass and body nutrients,” she stresses.
Dr Ndhlovu adds that more severe calorie restriction may cause other health problems such as reduced lean body mass and bone mineral density, and an increased risk for anaemia and gallstones. “Metabolism will slow down in people who restrict their calorie intake for a long period, which may take years to recover. If they then revert to their previous diets, calorie restrictors could see them put on more weight than they lost,” Dr Ndhlovu says.
She warns that there are certain individuals who should not consider going on the fast at all, they include: Diabetics (consult with your doctor) People with other metabolic disorders High risk individuals: the young, elderly and/or underweight Pregnant woman
CONSIDERATIONS TO MAKE BEFORE GOING ON IF
As is with any dietary change, there are important considerations you must contemplate before deciding on an eating pattern/diet. Mapholi says the most important thing to do before becoming an intermittent faster is to consult with a dietician or a doctor.
“You cannot really make this health decision on your own without consulting a healthcare professional, as there’s no conclusive research on the safety of the diet, especially in the long term. The healthcare professional will conduct a medical assessment to identify whether the fasting method is safe for the patient or not,” Mapholi says, emphasising that fad diets come and go. “Intermittent fasting is not excluded from this, it will soon blow over and another fad diet will make waves.”
Both Mapholi and Dr Ndhlovu agree that nothing can replace a balanced regimen of a moderate caloric intake and physical activity. In fact, Dr Ndhlovu even goes as far as to say that she does not personally advocate for the diet, mainly because it’s not easy to sustain.
Intermittent fasting is clearly a diet that can be great for some but no so much for others. What’s important is finding an eating plan that works for you, fits into your lifestyle and one that you can maintain over a long period of time.