Intermittent Fasting

By RAEL KOPING, Registered Dietician, Cape Town

Yom Kippur is the one day of the year when most of us don’t eat. Although it should be a day of solemn reflection about our behaviour over previous months, many of us tend to focus more on the fact that we are not eating than on the spiritual issues. 

The time of year when Yom Kippur falls is also the start of the warmer months, and so we begin our annual quest to lose the weight needed to fit into our summer bodies during the December holidays. 

The concept of fasting for weight loss has become trendy in recent times. We hear about Intermittent Fasting (IF), which is a diet philosophy aiming to promote weight loss and improve health by using time-restricted feeding schedules. Some routines may feature fasting periods on alternate days, while others may have a daily routine with a limited eating window. An extreme, but popular version permits a 6-hour feeding window followed by 18 hours of fast. Practically, this may mean having breakfast at 11 am, and finishing dinner by 5 pm. The 5:2 regimen, on the other hand,  requires 2 full fasting days; 2 low calorie days; and 3 normal days per week.

To lose weight successfully, a calorie-restricted (CR) diet is recommended. Such a way of eating typically features a set amount of calories spaced evenly over the course of the day. Although effective, these programmes require monitoring and vigilance, and are historically difficult for people to adhere to. 

IF does not focus on calorie restriction, but is rather about intuitive voluntary eating over a specific time period. Its proponents maintain that this is a more natural state of food intake. It is broadly accepted that our bodies follow a circadian rhythm which permits the cells time to complete various incompatible processes. These functions are therefore not separated by space, but by time. Disrupted circadian rhythm, such as when we eat three meals a day in the conventional way, is linked to diseases of lifestyle and increased oxidative stress, while restoring the rhythm has been demonstrated in animal models to reverse these disease processes. The period of food restriction, some say exceeding 12 hours, is claimed to activate fat burning and stimulate autophagy, which is the process in which the cell destroys and removes ageing and damaged organelles. There may be various other neurological benefits and improvements in hormonal levels not seen in conventional CR diets of a comparable calorie level. 

While IF may be theoretically robust – leading to greater interest among academics and dieting elites – I think that we should look to the examples where it operates all the time. For instance, in the emerging world we have large populations for whom IF has always been a way of life because  meals are few and far between. These people are typically not the beneficiaries of the glowing health and longevity promised by the IF paradigm for perhaps a variety of reasons. IF has also been practised by Muslims during the month of Ramadan for centuries with highly individual personal responses. This observation is borne out by research indicating that, while IF can be highly beneficial, it is not specifically more so than a conventional CR diet.

In deciding if IF is for you, it is always best to consult with your healthcare professional. Your weight loss will only persist as long as you maintain the regimen. And factors such as a 4:30 pm dinner may initially be a lark, but the loss of the social rituals at dinner or having meals with friends can prove difficult to manage. 

There is not enough scientific research yet to determine the necessary periods of restriction for an IF diet. So, IF still exists as a fringe food movement. As such, it is susceptible to extremes where, if one day of restriction is good, then two days must be better. Such movements often attract extreme personalities who engage in addictive behavioural patterns that psychologists may interpret as binge purge cycles (periods of fanatical adherence alternating with binges or other excesses). If you recognise such behaviours in your own personality, then IF may prove a trigger for other addictive activities. Medically, IF carries the risk of dysglycemia (poor sugar regulation), and blood pressure fluctuations. So, while generally considered a viable dietary consideration, IF should be assessed in conjunction with your qualified healthcare professional.  

Wishing you a healthy and meaningful Yom Kippur and a gmar chatimah tovah.

Rael Koping is a registered dietician practising in Sea Point, Cape Town. Among many focus areas, he has extensive experience in prescribing healthy diets and weight loss diets. 

• Published in the September 2023 issue – Click here to start reading.

• To advertise in the Cape Jewish Chronicle and on this website – kindly contact Lynette Roodt on 021 464 6736 or email For more information and advertising rate card click here.

• Sign up for our newsletter and never miss another issue.

• Please support the Cape Jewish Chronicle with a voluntary Subscription for 2023. For payment info click here.

• Visit our Portal to the Jewish Community to see a list of all the Jewish organisations in Cape Town with links to their websites.

Follow the Cape Jewish Chronicle: Facebook | Instagram | Twitter | LinkedIn


Please enter your comment!
Please enter your name here