Meet The UK’s Most Popular Fasting Programme

The reduction in calories mimics your body’s response to traditional fasting methods, while the high-fat, low-carb food (think nut bars, pouches of olives, flax crackers and dried soup blends) forces your body to use energy from your fat stores. On the first day, you eat around 1,100 calories, which moves your body into a fat-burning state, preparing for cellular clean-up. On the second day, you eat around 800 calories, which ramps up fat-burning and kick-starts ketogenesis, which turns glucose into energy. On the third and fourth days, fat-burning and ketone production increase; on the final day, the fast is completed, and cellular cleaning temporarily continues. It’s recommended you complete the programme three to 12 times a year to maintain the benefits. 

Completing the ProLon programme just two or three times a year boosts the immune system, kick-starts the metabolism and increases energy and clarity. It could also cut the risk of heart disease, cancer, high cholesterol, inflammation and other diseases. “The idea is that the body switches from burning glucose for energy to burning fat, which leads to weight loss, improved metabolism and insulin sensitivity and reduced inflammation,” says Clarissa. “The calorie restriction triggers a metabolic shift in the body, increasing levels of human growth hormone, believed to promote cellular repair and regeneration. Throughout the diet, the body is also thought to activate autophagy, a process that helps to clear damaged cells and boost cellular renewal. The reduction in caloric intake during the diet may also help reduce inflammation in the body, alongside the removal of ultra-processed foods, poor quality fats, alcohol and sugar, which are believed to play a role in the development of many chronic diseases.”

Results vary from one person to another, but in trials of healthy people doing one ProLon fast a month for three months in a row, individuals lost an average of 5.7lbs and 1.6 inches off their waist measurement. “However, it’s important to remember that a certain amount of the weight loss will be water weight,” says Kim. “Eating smaller amounts of food also means there’s less in your digestive system, so not all weight loss you see on the scale will be fat loss. Taking measurements before and after your ProLon cycle can help you identify how effective ProLon is at helping you lose body fat.”

If you’re intrigued by the concept of fasting but aren’t sure where to start, ProLon could be worth a try. “In my experience, it works well for people who want to lose weight in a guided environment, as well as those who have trouble with yo-yo dieting,” says Clarissa. “It can also be helpful for people who want to reset cravings and snacking habits.”

The programme is very low in calories, which may not make it appropriate for everyone. “ProLon shouldn’t be used if you are under the age of 18, pregnant or breastfeeding, if you have a history of eating disorders or low blood pressure, or if you’re diabetic,” advises Clarissa. “It should also be avoided if you are an athlete or very active, as a low-calorie diet may impact your performance and ability to exercise.” If you are in any doubt, chat to a healthcare professional before starting ProLon, or any diet, to ensure it’s safe and appropriate for your health needs and goals. 

“We have received endless positive feedback from clients who have experienced the benefits of the ProLon fast,” Kim tells us. “The most commonly reported benefits run from fat loss and reduced bloating to improved mindfulness around food.” 

ProLon costs £199 for a five-day programme, which works out at around £40 per day. If you decide to subscribe to do multiple fasts throughout the year, you’ll save £10 per fast.