Research has shown time and time again that extreme dieting is a very bad idea. Not only does it promote a turbulent relationship with food, it can wreak havoc with the metabolism – making it even more difficult to lose weight later in life. But until we were privy to this research out of the University of Oxford, we didn’t realise just how detrimental drastically restricting your calorie intake could be.
The study used magnetic resonance imaging (aka, MRI) to investigate how eating less than 800 calories per day impacted a person’s heart function and the distribution of fat cells in their liver and abdomen.
In as little as a week, the participants saw improvements in insulin resistance, cholesterol levels, triglycerides, glucose and blood pressure. They also lost 6 per cent on average of their total body fat. However, instead of being excreted through their lungs, sweat and urine, this fat was actually released into the bloodstream and absorbed by the heart. This led to heart-fat levels increasing as much as 44 per cent, and a notable deterioration in the organs function, including its ability to pump blood around the body.
“The metabolic improvements with a very low-calorie diet, such as a reduction in liver fat and reversal of diabetes would be expected to improve heart function. Instead, heart function got worse in the first week before starting to improve,” Dr Jennifer Rayner, clinical research fellow at Oxford University told The Telegraph UK.
“The sudden drop in calories causes fat to be released from different parts of the body into the blood and be taken up by the heart muscle. The heart muscle prefers to choose between fat or sugar as fuel and being swamped by fat worsens its function.”
Dr Rayner warned that caution should be exercised in those with existing heart problems as crash dieting could exacerbate their condition.
“If you have heart problems, you need to check with your doctor before embarking on a very low-calorie diet or fasting,” she told the publication.”
“People with a cardiac problem could well experience more symptoms at this early time point, so the diet should be supervised.”