Crash diets can cause transient deterioration in heart function

February 2, 2018, European Society of Cardiology

Crash diets can cause a transient deterioration in heart function, according to research presented today at CMR 2018. Patients with heart disease should seek medical advice before adopting a very low calorie diet.

"Crash diets, also called meal replacement programmes, have become increasingly fashionable in the past few years," said lead author Dr Jennifer Rayner, clinical research fellow, Oxford Centre for Magnetic Resonance, University of Oxford, Oxford, UK.

"These diets have a very low calorie content of 600 to 800 kcal per day and can be effective for losing weight, reducing blood pressure, and reversing diabetes," she added. "But the effects on the heart have not been studied until now."

This study used imaging (MRI) to investigate the impact of a very low calorie on and the distribution of fat in the abdomen, liver, and heart muscle.

The study included 21 obese volunteers. The average age was 52 years, average body mass index (BMI) was 37 kg/m2, and six were men. Participants consumed a very low calorie diet of 600 to 800 kcal per day for eight weeks. MRI was performed at the start of the study and after one and eight weeks.

After one week, total body fat, visceral fat and had all significantly fallen by an average of 6%, 11%, and 42%, respectively. This was accompanied by significant improvements in insulin resistance, fasting total cholesterol, triglycerides, glucose and blood pressure.

However, after one week, heart fat content had risen by 44%. This was associated with a deterioration in heart , including the heart's ability to pump blood.

By eight weeks, heart fat content and function had improved beyond what they had been before the diet began and all other measurements including body fat and cholesterol were continuing to improve.

Dr Rayner said: "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."

"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," she continued. "The prefers to choose between fat or sugar as fuel and being swamped by fat worsens its function. After the acute period in which the body is adjusting to dramatic calorie restriction, the fat content and function of the heart improved."

More research is needed to discover the impact of the acute reduction in heart function. In people with existing heart problems it might exacerbate their condition - for example aggravating heart failure symptoms like shortness of breath or increasing the risk of arrhythmias.

Dr Rayner said: "If you have heart problems, you need to check with your doctor before embarking on a very or fasting. People with a cardiac problem could well experience more symptoms at this early time point, so the diet should be supervised."

She added that very low calorie diets do have benefits and do not need to be avoided. "Otherwise healthy people may not notice the change in function in the early stages," she said. "But caution is needed in people with ."

Explore further: Back to basics for heart health

More information: The abstract "'Crash diets' cause acute impairment of cardiac function with associated myocardial lipid accumulation" will be presented during Poster Session 1 on 2 February 2018.

Related Stories

Back to basics for heart health

February 2, 2018
As heart month kicks off, doctors at Baylor College of Medicine say the first step to taking control of your health and preventing cardiovascular disease is understanding the basics and what they represent for your heart.

High BMI and blood pressure create a heavy heart

October 4, 2017
Being overweight or obese creates damaging changes to the structure of the heart, according to new research led by Queen Mary University of London (QMUL).

Diet low in specific amino acids may be the key to weight loss

December 21, 2017
A worldwide epidemic of diabetes and obesity has led many individuals to try to lose weight by dieting - but reduced-calorie diets are notoriously difficult to maintain. New research published in the Journal of Physiology ...

Restricted calorie diet improves heart function in obese patients with diabetes

November 28, 2011
A low-calorie diet eliminates insulin dependence and leads to improved heart function in obese patients with type 2 diabetes, according to a study presented today at the annual meeting of the Radiological Society of North ...

Weight loss after bariatric surgery can improve heart health

October 25, 2017
In overweight and obese people, fat often gets deposited in the midsection of the body. Large amounts of this belly fat can lead to unhealthy changes in a heart's function and size. But according to new findings presented ...

How a low-calorie diet could extend lifespan

June 29, 2016
Overeating can lead to health issues that can shorten one's life, such as obesity, diabetes and heart disease. On the other end of the spectrum, several studies have shown that restricting calorie intake below what a normal ...

Recommended for you

New link found between alcohol, genes and heart failure

May 25, 2018
The researchers investigated faulty versions of a gene called titin which are carried by one in 100 people or 600,000 people in the UK.

Study examines the rise of plaque in arteries

May 25, 2018
The accumulation of cholesterol plaques in artery walls can lead to atherosclerosis, or the hardening of arteries that contributes to heart attacks and strokes. In a new study, Yale researchers investigate how plaque cells ...

Low-dose aspirin could help pregnant women with high blood pressure avoid a dangerous condition

May 25, 2018
A daily dose of aspirin could help pregnant women in the first stage of high blood pressure avoid a condition that puts both mother and baby in danger, according to a new study.

Study shows in-home therapy effective for stroke rehabilitation

May 24, 2018
In-home rehabilitation, using a telehealth system and supervised by licensed occupational/physical therapists, is an effective means of improving arm motor status in stroke survivors, according to findings presented by University ...

Surgery involving ultrasound energy found to treat high blood pressure

May 23, 2018
An operation that targets the nerves connected to the kidney has been found to significantly reduce blood pressure in patients with hypertension, according to the results of a clinical trial led in the UK by Queen Mary University ...

New guidelines mean 1 in 3 adults may need blood pressure meds

May 23, 2018
(HealthDay)—One out of every three U.S. adults has high blood pressure that should be treated with medication, under guidelines recently adopted by the two leading heart health associations.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.