Counting calories: Eating less may reduce risk of heart attack, study finds

15 Jul 2019 --- Restricting calorie intake moderately can significantly reduce the risk of heart attack in people only marginally overweight, a new study from the University of Sydney, Australia has found. In addition to significantly improving conventional cardiometabolic risk factors, reducing the risk of cardiovascular disease CVD by about a factor of 13, trial participants also enjoyed major improvements on a range of risk factors linked to problems such as Type 2 diabetes, stroke, inflammation and some forms of cancer. The researchers note that the findings could point to proactive measures and preventative treatment for non-communicable diseases such as CVD.

The study, published in the journal Lancet Diabetes & Endocrinology, followed healthy, relatively young people and revealed the large impact that just a little bit of weight loss can have. It was also the first international study of moderate calorie restriction in non-obese people with clinically normal risk factors centered in the US.

“This is the first time, to our knowledge, that the results of moderate calorie restrictions have been analyzed in non-obese people with clinically normal risk factors,” says Professor Fontana, senior author of the study. “There’s no other drug that can achieve these reductions across all conventional cardiometabolic risk factors that we did – through a marginal reduction in calorie intake while providing all the essential vitamins and minerals with food.” 

 Participants on calorie control were fed a healthy diet, with the reduction in abdominal fat being an essential aspect in accounting for the improvements.The randomly controlled two-year study was coined Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE). The study, which was conducted across three clinics in the US and coordinated at Duke University, shows outcomes are optimized when weight loss is sustained, with some benefits only observed after one year.

The paper also notes that the significant reduction achieved in this study across all conventional cardiometabolic risk factors to better-than-normal levels, meant participants should enjoy the 13-times lesser risk of developing cardiovascular disease than people aged 50+ with two or more abnormal risk factors, according to previous research.

Professor Fontana said the findings provide further evidence that the trillions of dollars spent every year globally to treat highly prevalent chronic diseases might be better focused on prevention through the implementation of healthy lifestyle practices.

“Modern medicine focuses on diagnosing and treating clinically evident chronic diseases, which are largely preventable, one at a time, mainly with drugs and surgery,” notes Professor Fontana.

“The problem of this approach is that many age-associated chronic diseases – including cardiovascular disease – begin early in life and progress over decades of unhealthy diet and lifestyles, which trigger a wide range of physiologic, metabolic and molecular alterations deeply influencing the initiation, progression and prognosis of multiple medical conditions,” he adds.

Professor Fontana also explains that even healthy young and middle-aged people can benefit from focusing on their calorie intake, with indications that in general, even minor changes at any time of life could make a big difference.

“This should provide an important new tool in fighting the ravages of the 21st-century Western-style lifestyle, with cardiovascular disease continuing to be the leading cause of death and disability worldwide,” Professor Fontana concludes.

The trial involved 10,856 participants, aged 21 to 50 years old. Ultimately, 117 on the diet and another 75 put in the control group completed the study. Participants on calorie control were fed a healthy diet, with the reduction in abdominal fat being an essential aspect in accounting for the improvements identified in the study. The research was supported by the US’ National Institute on Aging (NIA) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

More data from the study
By reducing calorie intake by a mean of 11.9 percent, conventional cardiometabolic risk factors were reduced significantly. Other significant improvements were recorded in insulin resistance; metabolic syndrome – which is also linked to Type 2 diabetes, stroke and cancer; and c-reactive protein – a marker of inflammation, which is behind some of the most challenging diseases.

The researchers also note three ways to potentially reduce heart health-related issues. Restricting calorie intake just a bit can make a big difference, they say. In addition, it is almost impossible to overeat high fiber plant-based food, while exercise can also boost results.

Overeating has become a common phenomenon among consumers. Increases in the portion sizes of commercially available food products are known to cause “passive” overeating and have been linked to the emergence of the worldwide obesity crisis. Research from the University of Liverpool suggested that public health bodies are currently promoting is that the food industry needs to reduce the portion sizes of the products they are selling. Moreover, the British Nutrition Foundation (BFN) released a practical guide to navigating food portion sizes by simply using one’s hands or a spoon.

Edited by Kristiana Lalou