Features February 2012 Issue

Calorie Restriction Boosts Heart Function in Diabetes Patients

Research also shows that cutting calories can help reduce the amount of dangerous fat that accumulates around the heart.

Weight loss has long been the recommendation for many patients with type 2 diabetes. That’s because chemicals in fat diminish your body’s ability to use its own insulin. When the pancreas tries to make more insulin to compensate, the insulin-producing part of the pancreas can essentially wear out over time.

The protective sac surrounding the heart is the pericardium. Pericardial fat, located between this sac and the heart wall, is thought to produce inflammatory cytokines at a higher rate than fat located in other places in the body.

But researchers now have evidence that eating a low-calorie diet may not only help eliminate insulin dependence, but it may help improve heart function in obese patients with type 2 diabetes. Those are the findings of a study presented at the Radiological Society of North America in November 2011.

Researchers used cardiac magnetic resonance imaging (MRI) to analyze cardiac function and pericardial fat in 15 patients with type 2 diabetes. These patients were on strict 500-calorie-per-day diet for four months, and experienced significant reductions in pericardial fat and improved heart function.

While such a severe calorie-restricted eating plan shouldn’t be sustained over the long run and definitely shouldn’t be attempted without a doctor’s supervision, it does suggest that reducing calorie intake can have a positive effect on heart health.

Cleveland Clinic dietitian and diabetes educator Andrea Dunn, RD, LD, CDE, says it’s important that people understand the nature of fat in their bodies, and that it’s about more than appearance.

“Most people think of fat as something ornamental on their body­—here on the hips, here at the belly are, but fat can also accumulate around the organs, such as the heart,” she says.

“Fat is not dead ornamental tissue. It is live tissue. Fat can secrete chemicals that cause inflammation. It is thought that inflammatory cytokines like IL-6 increase the chances of developing atherosclerosis. This pericardial fat is thought to produce these cytokines at a higher rate than fat located in other places in the body. Losing even a small amount of weight, even if you remain overweight, seems to still benefit the body. So losing fat weight by following a low-calorie diet reduces the amount of cytokines produced: less fat, fewer cytokines.”

Dunn adds that reducing weight also helps with the insulin resistance problem, because your body more efficiently use the insulin it does produce, while also needing to produce less insulin.

Your Calorie Needs
How many calories you need to lose weight depends on many factors, Dunn says, including height, weight, age, gender, and genetics.

She notes that research has shown approximately how many calories per day be consumed healthily while still leading to weight loss. One major study showed that individuals could lose one to two pounds a week with the following calorie intake guidelines: 1,200 kcal/day (33 g fat) for participants with an initial weight of 120 to 170 lbs.; 1,500 kcal/day (42 g fat) for participants with a weight of 175 to 215 lbs.; 1,800 kcal/day (50 g fat) for participants with a weight of 220 to 245 lbs.; and 2,000 kcal/day (55 g fat) for participants weighing more than 250 lbs.

Getting Started
If you have diabetes and you’re ready to start cutting calories, adjusting your eating style and exercising more, consult with your doctor first.

“For those taking Coumadin or similar medications, those taking diabetes medications that lower blood sugar, and those taking blood pressure medications, significant changes in diet and exercise may need reduction or changes in the amount of medication needed,” Dunn says.

She adds that having modest and realistic goals at the start will help. Don’t feel pressured to make drastic dietary changes overnight or lose a huge number of pounds quickly. Slower changes that you incorporate into your life will stay with you longer.

“Know that even small changes can make a big difference,” Dunn says. “Studies such as the 2002 Diabetes Prevention Program and others since this study have shown that losing seven percent of body weight over a six-month period, and moderate exercise of 150 minutes or more per week can reduce insulin resistance and improve heart health.”