Slowing down the speed at which you eat, along with cutting out after dinner snacks and not eating within 2 hours of going to sleep may all help to shed the pounds, suggests research published in the online journal BMJ Open.
Changes in these eating habits were strongly associated with lower obesity and weight (BMI), and smaller waist circumference, the researchers found. They base their findings on health insurance data for nearly 60,000 people with diabetes In Japan who submitted claims and had regular health check-ups between 2008 and 2013.
The claims data included information on the dates of consultations and treatments, while the check-ups included measurements of weight (BMI) and waist circumference, and the results of tests for blood chemistry, urine, and liver function.
During the check-ups, participants were asked about their lifestyle, including their eating and sleep habits as well as alcohol and tobacco use. They were specifically asked about their eating speed, which was categorised as fast, normal, or slow. And they were asked whether they did any of the following three or more times a week: eat dinner within 2 hours of going to sleep; snack after dinner; and skip breakfast.
Around half of the total sample (just under 52%) changed their eating speed over the course of the six years. At the start of the study, some 22,070 people routinely wolfed down their food; 33,455 ate at a normal speed; and 4192 lingered over every mouthful. The slow eaters tended to be healthier and to have a healthier lifestyle than either the fast or normal speed eaters.
All the aspects of eating and sleeping habits studied, as well as alcohol consumption and previous obesity–defined as a BMI of 25 kg/m2–were significantly associated with obesity.
After taking account of potentially influential factors, the results showed that compared with those who tended to gobble up their food, those who ate at a normal speed were 29 percent less likely to be obese, rising to 42 percent for those who ate slowly.
And although absolute reductions in waist circumference–an indicator of a potentially harmful midriff bulge–were small, they were greater among the slow and normal speed eaters.
Snacking after dinner and eating within 2 hours of going to sleep 3 or more times a week were also strongly linked to changes in BMI. But skipping breakfast wasn’t.
This is an observational study, so no firm conclusions can be drawn about cause and effect, added to which eating speed was based on subjective assessment, nor did the researchers assess energy intake or physical activity levels, both of which may have been influential.
Nevertheless, eating quickly has been linked to impaired glucose tolerance and insulin resistance. This is possibly because it may take longer for fast eaters to feel full, whereas this might happen more quickly for slow eaters, helping to curb their calorie intake, the researchers suggest.
And they conclude: “Changes in eating habits can affect obesity, BMI, and waist circumference. Interventions aimed at reducing eating speed may be effective in preventing obesity and lowering the associated health risks.”
Effects of changes in eating speed on obesity in patients with diabetes: a secondary analysis of longitudinal health check-up data
Yumi Hurst, Haruhisa Fukuda
Objective Few studies have examined the causal relationships between lifestyle habits and obesity. With a focus on eating speed in patients with type 2 diabetes, this study aimed to analyse the effects of changes in lifestyle habits on changes in obesity using panel data.
Methods Patient-level panel data from 2008 to 2013 were generated using commercially available insurance claims data and health check-up data. The study subjects comprised Japanese men and women (n=59 717) enrolled in health insurance societies who had been diagnosed with type 2 diabetes during the study period. Body mass index (BMI) was measured, and obesity was defined as a BMI of 25 or more. Information on lifestyle habits were obtained from the subjects’ responses to questions asked during health check-ups. The main exposure of interest was eating speed (‘fast’, ‘normal’ and ‘slow’). Other lifestyle habits included eating dinner within 2 hours of sleeping, after-dinner snacking, skipping breakfast, alcohol consumption frequency, sleep adequacy and tobacco consumption. A generalised estimating equation model was used to examine the effects of these habits on obesity. In addition, fixed-effects models were used to assess these effects on BMI and waist circumference.
Results The generalised estimating equation model showed that eating slower inhibited the development of obesity. The ORs for slow (0.58) and normal-speed eaters (0.71) indicated that these groups were less likely to be obese than fast eaters (P<0.001). Similarly, the fixed-effects models showed that eating slower reduced BMI and waist circumference. Relative to fast eaters, the coefficients of the BMI model for slow and normal-speed eaters were −0.11 and −0.07, respectively (P<0.001).
Discussion Changes in eating speed can affect changes in obesity, BMI and waist circumference. Interventions aimed at reducing eating speed may be effective in preventing obesity and lowering the associated health risks.
This study analysed Japanese men and women who had undergone specific health check-ups regardless of obesity status. Possible lifestyle-related determinants of obesity were identified using questionnaire items from the Standard Health Check-up and Counselling Guidance Programme.12 We examined 6-year panel data to determine how changes in eating speed and other lifestyle habits affect obesity and BMI. The main results indicated that decreases in eating speeds can lead to reductions in obesity and BMI after controlling for the covariates. In addition, the study found that the cessation of eating after dinner or within 2 hours before sleeping would also have a similar effect on reducing excess body weight.
A strength of this study is the usage of large-scale panel data from approximately 60 000 patients with diabetes spanning a 6-year observation period. The use of panel data increases the accuracy of estimates when compared with conventional cross-sectional and time series data.17 Panel data also enable adjustments of the unobservable differences between study subpopulations, thereby facilitating analyses of the effects of behavioural changes in subjects. Another strength of this study is the incorporation of data on lifestyle habits, such as eating, sleeping and smoking. By analysing the associations between these habits and obesity, our study was able to quantify the possible effects of changes in these habits on obesity.
The major finding of this study is that changes in eating speed can affect obesity, BMI and waist circumference. The control of eating speed may therefore be a possible means of regulating body weight and preventing obesity, which in turn reduces the risk of developing non-communicable diseases. Eating quickly is associated with impaired glucose tolerance and insulin resistance,18 19 and is a known risk factor for diabetes through increases in body weight.20 Other studies have also reported associations between eating quickly and increased BMI, indicating that eating speed is a contributing factor for obesity.7 8 21–26 A possible reason for this association is that fast eaters may continue to eat until they feel full despite having already consumed an adequate amount of calories, and the combined effect of eating quickly and overeating may contribute to weight gain.27 In contrast, eating slowly may help to increase feelings of satiety before an excessive amount of food is ingested.28–30 A prospective study of schoolgirls found that the reduction of eating speed was able to suppress weight gain and prevent obesity.31 The findings of these studies are consistent with those of our analysis.
In addition to BMI-based definitions of obesity, waist circumference-based definitions of abdominal obesity have also become increasingly important in recent years. Cerhan et al proposed that assessments of waist circumference should accompany assessments of BMI.32 As a supplementary analysis, we employed a fixed-effects model to examine the effects of changes in eating speed on waist circumference in our subjects. The results showed that when compared with fast eaters, normal-speed eaters and slow eaters had reductions in waist circumference of 0.21 cm and 0.41 cm, respectively (P<0.001). These results support our findings of the effects of changes in eating speed on obesity.
Our results also indicated that frequently eating dinner within 2 hours before sleeping, snacking after dinner and skipping breakfast contribute to the development of obesity. Previous studies have identified eating after dinner and within 2 hours before sleeping as risk factors of metabolic syndrome.7 This supports our findings that the cessation of these habits can help to reduce obesity and BMI. Skipping breakfast has also been shown to be associated with excess weight and obesity, and is a risk factor of metabolic syndrome.7 9 33 Our generalised estimating equation model revealed that consistently eating breakfast can reduce obesity, which also corroborates the findings of previous studies. However, our fixed-effects model showed that consistently eating breakfast did not affect changes in BMI. It has been reported that skipping breakfast over a long period is associated with high BMI and elevated cardiometabolic risks.34 Consistently eating breakfast may therefore help to control obesity and BMI.
The association between daily alcohol consumption and obesity remains controversial. While several studies have identified this lifestyle habit as a risk factor of metabolic syndrome,7 35 others have reported an inverse association between the frequency of alcohol consumption (given the same quantities of alcohol) and obesity.36 37 In our study, the frequency of alcohol consumption was found to be inversely associated with obesity, but positively associated with BMI and waist circumference. In order to clarify this apparent disparity, further analyses of alcohol consumption should be conducted with consideration to the overall quantities of alcohol consumed.
Studies have also found associations between short sleep durations and BMI increases, and that poor-quality sleep is associated with metabolic syndrome.38–40 Our analysis produced contradictory results in that a change from adequate sleep to inadequate sleep would reduce BMI but increase obesity progression. Moreover, we did not detect any significant association between sleep and waist circumference. A recent study has shown that unstable sleep patterns may increase the quantity of food intake,41 and our findings therefore require further investigation. The lack of association between habitual smoking and BMI or metabolic syndrome has been reported in previous studies,7 42 which corroborates our findings.
This study has several limitations that should be considered. First, this study used health check-up data from health insurance societies. As a result, the data may not have included a large proportion of the insurance enrollees’ dependents. In particular, there was a relatively small proportion of older adults in our study population. The results may therefore lack generalisability to other subpopulations. Second, eating speed and the other lifestyle habits were self-assessed, and may therefore be vulnerable to reporting bias. However, while the differences in perceptions of eating and sleeping habits in standardised questionnaires have been described,43 Sasaki et al reported that there was no difference between the eating speeds assessed by study subjects or by friends of the subjects.25 In addition, our findings are consistent with those of a previous study that used objective measures of eating speed and found that slower eating speeds were associated with greater weight loss.30 Third, we did not include an analysis of physical exercise and energy intake, which may be potential confounders. Nevertheless, a previous analysis has reported that eating speed was associated with obesity regardless of the level of physical activity.26 Other studies have also reported similar associations between eating speed and BMI given similar overall food intake, which corroborates our findings.24 25 Therefore, these two factors are unlikely to be confounders in this study despite their association with BMI. Finally, the sample comprised relatively health-conscious individuals who voluntarily participated in health check-ups. The findings may therefore have limited applicability to less health-conscious people.
Many studies have shown that eating habits are associated with BMI and weight gain.7 8 18–31 However, this study used panel data to show that changes in eating habits have a strong relationship with obesity, BMI and waist circumference. These findings indicate that weight loss can be supported through the reduction of eating speed, the cessation of eating dinner within 2 hours before sleeping, the cessation of snacking after dinner and consistently having breakfast.
Changes in eating habits can affect obesity, BMI and waist circumference. Interventions aimed at altering eating habits, such as education initiatives and programme to reduce eating speed, may be useful in preventing obesity and reducing the risk of non-communicable diseases.
Contributors YH contributed to data analysis and interpretation, and drafting of the manuscript. HF contributed to the study concept, design and interpretation and drafting of the manuscript.
Funding This work was supported by Grant-in-Aid for Health Sciences Research by the Ministry of Health, Labour and Welfare of Japan (Grant Number H29-Seisaku-Shitei-010).
Competing interests None declared.
Patient consent Not required.
Ethics approval This study was approved by the ethics committee of the Japan Medical Data Center (No. 18-09-2014).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.