Could short-term overeating increase your risk of pre-diabetes?

Dr Gunveen Kaur is exploring whether the human body’s response to short-term overeating could offer a clue to a predisposition for type 2 diabetes. 

Scientists already know that a short-term high-calorie, high-fat diet can increase the risk of insulin resistance and glucose intolerance in healthy people. It increases inflammation and disrupts skeletal muscle insulin action, increasing the risk of pre-diabetes (higher than normal blood glucose levels and/or poor insulin action). 

Through a Diabetes Australia Research Program grant, Dr Kaur is drilling down to further understand what happens in the body during and after a seven-day high-calorie, high-fat diet. She is investigating whether such a diet impairs insulin-stimulated blood flow to muscle cells, and if impairment in blood flow occurs before the insulin resistance. 

Evidence from animal studies indicates that a high-fat diet leads to poor blood flow in the smallest blood vessels in the body (known as microvascular blood flow) and that this occurs before whole body insulin resistance develops. But so far there is no equivalent data in humans.  

Dr Kaur hopes this study will provide a similar understanding of how our cardio-metabolic system responds to high-fat, high calorie diet, as well as a better sense of the timing of the response. 

“If we are able to show that in healthy humans, impaired muscle microvascular blood flow occurs before the insulin resistance or glucose intolerance develops, we have an opportunity to find ways to protect against these effects which could otherwise lead to pre-diabetes,” she said. 

“For example, we will explore whether increasing polyunsaturated fats and reducing saturated fat protects the smallest blood vessels from the detrimental effects of overfeeding.”  

The study involves 14 healthy adults aged between 18 and 45 adhering to a seven-day high-calorie, high-fat diet. 

On top of their usual diet, participants are provided with prescribed snacks to eat over the seven days. The snacks add around 50 per cent to their daily calories and approximately 55 grams of additional fat per day. The snacks are personalised based on each individual’s energy intake. 

Participants have their blood glucose, plasma insulin and muscle microvascular blood flow measured before, during and after the seven days. 

“This study will be the first to show whether just seven days of high-calorie, high-fat feeding is enough to disrupt microvascular function, and if this contributes to an increased risk of pre-diabetes in healthy people,” Dr Kaur said.  

“If this is the case, dietary interventions could be used to prevent pre-diabetes in people with microvascular impairment.  

“Our findings could inform new dietary guidelines to prevent vascular dysfunction from high-calorie high-fat foods.”