‘Intermittent fasting is not the cure-all’: Dr Karan busts the biggest women’s health myths

Intermittent fasting promises to hack biology, achieve weight loss and a gut health boost without changing what you are eating, only the timeframe you are eating it in.

But simply condensing meals into an eight-hour window isn’t a “panacea for health or wellness”, Dr Karan Rajan has told The Independent’s Well Enough podcast. “There is no significant benefit in prolonged fasting beyond the fasting that you can get overnight.”

The NHS surgeon, who is one of the biggest health and science content creators on social media, with 2.1 million followers on Instagram, explained there is some evidence that fasting could increase levels of beneficial bacteria, which strengthens the gut lining and clears up debris in the cells.

Skipping breakfast and eating the first meal of the day at lunch may also make it easier to stick to a calorie deficit and lose weight. Dr Rajan said: “It becomes easier to divide your calories across two meals instead of three meals.”

Instead of going hours without eating, Dr Rajan explained that a fast can be achieved by increasing the gap between the last meal of one day and the first of the next. For example, not eating dinner after 7pm and eating breakfast at 9am or 10am. That will create a 14 to 15-hour fast.

However, if you are active during the day, pregnant, have heavy periods, or if you are a child, elderly or on medications, then a fast can be “counterintuitive”, he warned.

“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. And actually, you don’t need to do any fancy, fast, or protocol to have good health,” Dr Rajan said.

In fact, intermittent fasting could come with serious risks. One large-scale study by researchers in the US and China found that those who confined their eating to less than eight hours a day faced a 135 per cent higher risk of dying from cardiovascular disease than those who ate within a 12- to 14-hour window.

It also affects men and women differently, with one Indian study involving rodents suggesting intermittent fasting may cause changes in oestrogen levels and negatively affect reproductive functions, such as menstrual regularity, fertility, pregnancy, and lactation.

“I wouldn’t know in what sense or scenario a detox would be an appropriate therapy for anyone,” Dr Rajan said.

In general, a detox is just a way of “hyping” simple protocols that already exist.

For example, if someone is suffering from bloating, it is best to avoid grazing or snacking constantly throughout the day.

“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,” Dr Rajan said.

If the body doesn’t clean up all the dirt and debris, it will ferment and cause gas and bloating.

“So that is a ‘hack’ or a ‘protocol’ or if you really stretch the term, that’s a detox in a sense,” he added.

Intermittent fasting is also said to help manage a leaky gut – a condition where the gut lining allows partially digested food or toxins through into your bloodstream.

But Dr Rajan stresses this is not a diagnosis on its own and could be an indication of another serious condition, such as IBS, inflammatory bowel disease, or a gynaecological condition with GI 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. Like a lot of people who have IBS symptoms could have leaky gut symptoms. That could be things like bloating, pain, constipation, diarrhoea, excessive flatulence, maybe some acid reflux,” Dr Rajan said.

“Leaky gut on its own. If it’s really impacting someone’s life and life-limiting, then it should be a stepping stone to then a deeper line of inquiry to actually what is causing that,” he added.

Watch the full episode of ‘Well Enough’ with Dr Karan Rajan here, or listen on Spotify and Apple Podcasts.