The Independent's journalism is supported by our readers. When you purchase through links on our site, we may earn commission.
Intermittent Fasting: Not the Universal Health Solution Many Believe
Intermittent fasting has gained immense popularity as a biological hack promising weight loss and improved gut health without altering dietary content, merely by restricting eating windows. However, NHS surgeon Dr Karan Rajan, a prominent health and science creator with 2.1 million Instagram followers, has delivered a crucial reality check on The Independent's Well Enough podcast.
The Limitations of Condensed Eating Windows
Dr Rajan emphasises that simply compressing meals into an eight-hour timeframe does not constitute a "panacea for health or wellness." He explains, "There is no significant benefit in prolonged fasting beyond the fasting that you can get overnight." While some evidence suggests fasting may increase beneficial bacteria, strengthening the gut lining and clearing cellular debris, the surgeon cautions against viewing it as a one-size-fits-all solution.
For certain individuals, skipping breakfast and consuming the first meal at lunch might facilitate adherence to a calorie deficit, potentially aiding weight management. "It becomes easier to divide your calories across two meals instead of three meals," Dr Rajan notes. He suggests achieving a fast by extending the gap between the last meal of one day and the first of the next, such as finishing dinner by 7pm and breaking fast at 9am or 10am, creating a 14 to 15-hour window.
Significant Risks and Contraindications
Nevertheless, Dr Rajan issues stern warnings about intermittent fasting's potential dangers. For active individuals, pregnant women, those experiencing heavy periods, children, elderly people, or anyone on medications, fasting can prove "counterintuitive." He elaborates, "If you have specific medical conditions, if you're diabetic, if you've got other issues, hormonal issues, metabolic issues, nutrient absorption issues in those cases, something like a fast doesn't make sense."
Alarmingly, a substantial study conducted by researchers in the United States and China revealed that individuals restricting eating to less than eight hours daily faced a 135 per cent higher risk of dying from cardiovascular disease compared to those eating within a 12 to 14-hour window. Furthermore, intermittent fasting affects men and women differently; an Indian rodent study indicated it might alter oestrogen levels and adversely impact reproductive functions, including menstrual regularity, fertility, pregnancy, and lactation.
Detox Claims and Gut Health Misconceptions
Dr Rajan also scrutinises detox protocols, stating, "I wouldn't know in what sense or scenario a detox would be an appropriate therapy for anyone." He describes detoxes as merely "hyping" existing simple practices. For instance, avoiding constant grazing throughout the day can help manage bloating by allowing the migrating motor complex—intestinal peristaltic waves—to cleanse debris and dead cells. "Every time you eat, you don't allow the migrating motor complex, which is the wave of peristalsis in your body, in your intestines to clean up the debris and dead cells and microbes," he explains. Failure to clear this material leads to fermentation, causing gas and bloating.
Regarding leaky gut—a condition where the gut lining permits partially digested food or toxins into the bloodstream—Dr Rajan stresses it is not a standalone diagnosis but could indicate serious underlying issues like IBS, inflammatory bowel disease, or gynaecological conditions with gastrointestinal symptoms. "Leaky gut is not a diagnosis. It's not classified as a diagnosis, but it can signify some underlying symptoms, which could point to a specific GI condition," he says. Symptoms may include bloating, pain, constipation, diarrhoea, excessive flatulence, and acid reflux.
Dr Rajan concludes that while intermittent fasting offers benefits for some, it is far from a universal cure-all. "And actually, you don't need to do any fancy, fast, or protocol to have good health," he asserts, urging a more nuanced approach to wellness that considers individual health circumstances and avoids potentially harmful trends.
