Sleep well to avoid insulin resistance, researchers advise
Study coauthor Dr. Geng Zong, a research fellow at the Harvard T. H. Chan School of Public Health in Boston, MA, and colleagues suggest eating more meals prepared at home may reduce weight gain over time, which they say could explain their findings; excess weight is a risk factor for type 2 diabetes.
The negative health implications of regularly dining out in restaurants – particularly fast food restaurants – have been well documented.
Earlier this year, for example, Medical News Today reported on a study that found eating out leads to significantly higher calorie and salt intake, which may lead to weight gain and high blood pressure – risk factors for diabetes and heart disease.
But despite the associated health risks, it seems more of us are choosing to dine out rather than prepare home-cooked meals. Earlier this year, a report from the United States (US) Department of Commerce revealed that, for the first time in history, Americans are spending more money eating out than buying groceries.
"The trend for eating commercially prepared meals in restaurants or as take-out in the United States has increased significantly over the last 50 years," notes Zong. "At the same time, type 2 diabetes rates have also increased."
13 per cent lower type 2 diabetes risk with two homemade meals daily
For their study, Zong and colleagues set out to investigate whether increasing consumption of homemade meals may protect against type 2 diabetes.
The team assessed the homemade meal intake and the type 2 diabetes development of almost 58,000 women who were part of the Nurses' Health Study and more than 41,000 men who were part of the Health Professionals Follow-Up Study.
All participants were free of diabetes, cancer and cardiovascular disease at baseline and were followed for up to 36 years between 1986-2012.
Also, sleepless nights and a high-fat diet can both damage insulin sensitivity. This demonstrates the importance of a good night's sleep on health.
Sleep deficiency and a high-fat diet are known to lead to impaired insulin sensitivity, but it was previously unknown which leads to more severe insulin resistance.
Dr. Josiane Broussard, and colleagues from Cedars-Sinai Medical Center in Los Angeles, CA, used a canine model to examine whether sleep deprivation and a high-fat diet affect insulin sensitivity in similar ways.
When the body becomes less sensitive to insulin, in other words, insulin resistant, it needs to produce more insulin to keep blood sugar stable.
This may eventually lead to type 2 diabetes, where the body's insulin response does not work properly and there is too much sugar in the blood.
Diabetes entails a number of serious complications, including heart disease. Individuals with obesity are more likely to develop insulin resistance and subsequently, diabetes.
The researchers measured insulin sensitivity in eight male dogs before and after diet-induced obesity.
First, they deprived the dogs of 1 night's sleep, and then used an IV glucose tolerance test to measure insulin sensitivity. They compared the results with those of dogs that had a normal night's sleep. Then the dogs were fed a high-fat diet for six months, before being tested again.
One night of sleep deprivation reduced insulin sensitivity by 33 per cent, whereas six months of high-fat diet, reduced it by 21 per cent. Once the high-fat diet had caused insulin insensitivity, one night of sleep deprivation did not impair the insulin sensitivity further.
The study suggests that one night of total sleep deprivation may be as detrimental to insulin sensitivity as six months on a high-fat diet. It demonstrates the importance of adequate sleep in maintaining blood sugar levels and reducing risk for metabolic diseases like obesity and diabetes.
The findings suggest a similar mechanism by which both insufficient sleep and a high-fat diet induce insulin resistance. It also seems that after high-fat feeding, insulin sensitivity cannot be reduced further by sleep loss.
Apart from impaired insulin sensitivity, sleep deprivation can lead to increased food intake and overall increased risk for metabolic diseases.
Dr. Caroline Apovian, a fellow and spokesperson for The Obesity Society, says: "It is critical for health practitioners to emphasize the importance of sleep to their patients. Many patients understand the importance of a balanced diet, but they might not have a clear idea of how critical sleep is to maintaining equilibrium in the body."
Broussard calls for further research to examine the pathways that account for the interactions between sleep and diet and their relationship to insulin sensitivity, and also to determine whether insulin sensitivity improves after recovery sleep.
Through understanding the causes and complications of obesity and identifying the relevant mechanisms involved, scientists hope to find keys to its prevention or cure.
Medical News Today recently reported on research that suggested 6.5 hours a night might be a healthy amount of sleep.