Professor says one drink can burn belly fat while you sleep

A weight loss doctor says there is one drink he recommends before bed - and it’s not lemon water, protein shakes or green tea. Professor Franklin Joseph, medical director of Dr Frank’s Weight Loss Clinic, says that while many people unknowingly sabotage their overnight fat burning, there’s one drink that may help: plain, unsweetened kefir.

“Most people don’t realise the impact their evening choices have on overnight metabolism,” he said. “What you drink before bed matters - and kefir ticks a lot of boxes without spiking your blood sugar or messing up your sleep.”

Kefir is a fermented milk drink with natural probiotics, light protein, and bioactive compounds. And according to Prof Joseph, this mix of nutrients makes it an ideal evening choice for people trying to lose weight - or struggling with stubborn belly fat.

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“You want something that supports gut health, keeps blood sugar stable, and helps recovery while you sleep,” he said. “Kefir does all three.”

He said that, unlike sugary yoghurts or protein shakes, unsweetened kefir has a very low glycaemic load - meaning it won’t cause the insulin spikes that can interfere with fat burning and sleep quality. “We often see patients reach for what they think is a healthy drink at night - like a banana smoothie or a flavoured yoghurt drink,” Prof Joseph said. “But those can be loaded with hidden sugars that raise cortisol and keep your body in storage mode, not burn mode.”

Studies suggest fermented foods like kefir can improve insulin sensitivity, reduce inflammation, and support a healthier gut microbiome - all of which play key roles in fat loss. And when it comes to sleep, kefir may also help through the gut-brain axis - the communication network between your digestive system and central nervous system. A healthier gut has been linked to better sleep patterns and reduced hunger hormones the next day.

Prof Joseph recommends sticking to 100 to 150ml of plain kefir, around 30 to 60 minutes before bed. Avoid sweetened varieties, and don’t pair it with sugary snacks or carbs. “You want your body to be calm, nourished, and ready to repair overnight,” he said. “A small glass of kefir is simple - but powerful.”

Prof Joseph added: “Kefir won’t burn fat on its own, but if you’re already eating well and exercising, it could help tip the balance in your favour.”