Doctor's advice on how long people need to fast for to lose maximum weight

Dr Mindy Pelz said that people need to fast for up to 17 hours to achieve the maximum weight loss on her podcast

A diet and weight loss expert has revealed the optimal fasting period for maximum weight loss. Dr Mindy Pelz, in a video on her YouTube channel, addressed queries about how to maximise "top end weight loss".

The specialist, who has featured on the Diary of a CEO podcast, explained that people aim to kickstart the process of ketosis through fasting. This metabolic state, where the body burns fat instead of glucose for energy, is associated with potential benefits such as weight loss, increased energy, and management of chronic illnesses.

Dr Pelz also touched upon autophagy - a process where cells break down and eliminate old, damaged or abnormal proteins and other substances, which are then recycled for crucial cell functions, particularly during periods of stress or starvation. To initiate ketosis, she suggested that individuals likely need to fast for 13-15 hours. She stated: "So those of you that want to lose weight, that 13 to 15 hours is your first ledge to stimulate ketosis so that you burn fat in that moment.

"But here, think about this for a moment. That doesn't mean that you are going to kick yourself out of insulin resistance.

"So the name of the game when we're looking at using fasting as a really cool tool for weight loss is how do we not only burn fat but how do we stop you from becoming insulin resistant?" Intermittent fasting has been shown to have major benefits for insulin resistance and to lead to a reduction in blood sugar levels.

Insulin resistance is when cells in the muscles, fat, and liver don't respond well to insulin and can't easily take up glucose from the blood. As a result, the pancreas makes more insulin to help glucose enter your cells.

Dr Pelz said to avoid insulin resistance: "We've got to get you into this place of autophagy. So the second thing that we've got to think about is the longer you fast, the deeper the autophagy and the deeper the autophagy, the more your body gets rid of insulin-resistant cells.

"So that's 17 hours or longer. Now, you're in massive cellular repair. 13 to 15 hours, you're just burning fat from getting energy by burning fat, but you're not in cellular repair as deep. So make sure if you want to lose weight, you're going in longer than 17 hours."

Dr Pelz, discussing the timing of meals, advised that people should only eat during daylight hours. She explained: "So in the summer, this is a little bit easier because you can have dinner a little bit earlier.

"But as long as you're eating in the dark, you are promoting insulin resistance. So that dinner you have at nine o'clock at night when it's dark out or eight o'clock at night... when it's dark out, your cells are going to be more insulin resistant to that because Melatonin has come in."