Researchers Find Impaired Glucose Tolerance More Likely In Fast Eaters

A Japanese study has found that fast eaters may be at a significantly greater risk of developing impaired glucose tolerance compared to those who eat at a normal speed.

The study, which appeared online last month in the journal Diabetes Research and Clinical Practice, was conducted by researchers at the Institute of Clinical Medicine at the University of Tsukuba. The study involved 172 initially healthy Japanese men and women who were followed over 3 years. Participants were asked to report on various eating habits such as whether they were “fast eaters”, “snacked frequently”, “ate late at night”, “skipped meals”, or “ate out frequently”. Over the course of the study, 39 people developed impaired glucose tolerance (IGT) including 2 who went on to develop diabetes. The only self reported eating habit significantly associated with IGT was fast eating.

Self reported fast eating was associated with 2.47 times increased odds of developing IGT. Adjusting the results for various confounders including age, weight, smoking status, alcohol intake, and family history of diabetes, only marginally reduced the odds ratio to 2.43.

The study comes hot on the heels of a recent New Zealand study that found an increased risk of obesity in women who were fast eaters. Obesity is known to increase insulin resistance and the subsequent risk of developing diabetes however given the link between fast eating and IGT persisted even after adjusting for weight, it is likely that other mechanisms are at play.

One possible mechanism is that eating fast may lead to much higher blood glucose levels following meals. Continual spikes in blood glucose may, over time, reduce the effectiveness of insulin in controlling these spikes leading to poorer glycemic control.

Impaired glucose tolerance, which is also considered a type of pre-diabetes, occurs when blood glucose levels are higher than normal following a 2-hour oral glucose tolerance test (OGTT) but below the levels required for a diagnosis of diabetes to be made. A level less than 140 mg/dL after a 2-hour OGTT is considered normal, a level of between 141 mg/dL and 200 mg/dL is indicative of IGT or pre-diabetes, while a level above 200 mg/dL would suggest a diagnosis of full blown diabetes.

Around 15% of adult Americans have impaired glucose tolerance while a further 12% have diabetes.