- Weight gain is associated with impulsive eating that is not related to hunger.
- Research finds that many people eat somewhat randomly over the course of 15 hours per day.
- Time-restricted eating can be a way to control weight and improve health without adherence to calorie restriction.
Often in our attempts to battle weight and obesity, a system of calorie restriction is imposed. While many of these attempts result in short term weight loss, the effects are not sustainable in the long run. It is apparent that calorie restriction requires understanding, motivation, and self-control, which may be limited resources for many.
Many research studies have revealed that there is large group of people who are sensitive to food temptations, are distracted by food cues, and are prone to episodes of impulsive overeating. This group of people is understandably also prone to weight gain and eventual obesity.
Unfortunately, at least in first world countries like the United States, food is available all day long. Often the easiest foods to find and consume are “fast foods” which are highly palatable and calorie dense. It’s no secret that this environment can contribute to obesity. Indeed, our current environment is referred to as “obesogenic.”
For those with a tendency to impulsively eat, it is the highly palatable and calorie dense foods that are attractive. You don’t find people attracted to fruits and vegetables to satisfy an impulse or craving.
Research has shown that impulsive eating is a cognitive issue, and not an actual event related to hunger. Overeating is often associated with situations such as eating in the car, social situations, social isolation, going to restaurants, being tired, irritable, bored, depressed, and skipping meals.
Just how prevalent is this problem?
A study published in Cell Metabolism (2015) took advantage of the availability of a smartphone app to track eating patterns in healthy adults. Results showed that around half of those in the study reported eating for about 15 hours a day every day. These folks also showed a bias toward eating late in the day. Estimates showed that less than 25% of daily calories were consumed before noon, and over 37% of daily calories were being consumed after 6 p.m. In addition, the calories consumed later in the day tended to be higher in fat and calories.
Meals that were consumed took an average of only 14.5 minutes. This flies in the face of the very common advice to slow down and make a meal last at least 20 minutes to give your stomach a chance to register fullness.
This same study later identified those who were eating over 14 hours a day and asked for volunteers to participate in a 16-week period of limiting eating to a 10-11 hour window. There were no calorie restrictions or other limitations imposed. Again, the app was used to measure eating events and timing. After 16 weeks, study subjects experienced reduced body weight, felt more energetic, and had improvements in sleep. Significantly, these benefits lasted for over a year.
The benefits of fasting
For the past several decades, intermittent fasting has been recognized as a feasible way to limit calorie consumption. Fasting can take place for hours, days, or weeks, depending on the protocol. The app study used a daily fast of 10-11 hours a day with individuals self-selecting the preferred time. A daily fast of this type is actually referred to as time-restricted eating rather than intermittent fasting. Time-restricted eating usually refers to consolidation of feeding periods into somewhere between 6 and 10 hours daily.
There are measurable benefits to time-restricted eating even though there is no programmed alteration in diet quality or quantity.
Research has shown that eating more in line with our natural circadian rhythms has metabolic benefits that can impact our health. Keeping our eating more in line with daily light/dark cycles has been shown to reduce body weight, improve glucose tolerance, reduces blood lipids, improve blood pressure, and improve gut function. There are also positive effects on appetite-related hormones. Some studies report that after a period of time-restricted eating, cravings for night-time eating disappear and sleep improves. Other studies have discovered that these metabolic benefits will also occur even if there is no weight loss.
Leveraging the concept of time-restricted eating
Given that many individuals struggle with how they eat and when, using time-restricted eating could be a more effective tactic than attempting a much more complex dieting regimen. The gist of it is that an individual only has to pay attention to one rule. It is not a calorie restriction, with its set of complex behaviors. For example, it’s just “I don’t eat between 7 p.m. and 7 a.m.” One rule, one idea.
Does this lead to bingeing during the non-fasting hours? Research says no. As time goes on, a person gets used to eating less during fasting times and does not feel the need to binge.
Another potential benefit is that individuals can begin to adjust to not using food in situations that are not related to hunger. This can create a certain mindfulness.
Mindfulness has been shown to be an effective treatment for obesity, but the effect often wanes if mindfulness treatment is not continued. Studies using time-restricted eating report very high compliance, with many individuals continuing the eating pattern after the study is over.
It would appear that time-restricted eating has great potential for helping people stop falling into the many traps inherent in our obesogenic culture. Is it that simple? Perhaps not, because we still have eating at night for social events, movies, sporting events, and going out to restaurants. But we need to do our best to take advantage of the obvious benefits. We can work with people to self-select the desired fasting hours, and widen the window to 12 hours. Even this period of fasting has been shown to have positive results which are felt and observed by participants.
Our bodies have evolved over millions of years to cope very well with fasting. If they hadn’t, we would not have survived. Eating at all hours of the day has been shown to be bad for our health. We can begin to get back to how our bodies are designed to be and eating patterns that are optimal for us by taking advantage of what is now known as time-restricted eating.
Gill, S., and Panda, S. (2015). A Smartphone App Reveals Erratic Diurnal Eating Patterns in Humans that Can Be Modulated for Health Benefits. Cell Metabolism. 22:789-798.
Regmi, P, and Heilbronn, L.K. (2020). Time-Restricted Eating: Benefits, Mechanisms, and Challenges in Translation. iScience. 23, 101161.
Schlundt, D.G., Hill, J.O., Sbrocco, T., Pope-Cordie, J., Kasser, T. (1990). Obesity: a biogenetic or biobehavioral problem. International Journal of Obesity. 14(9):815-828.
Geisen, J.C.A.H., Havermans, R.C., Jansen, A. (2008). Weight, gender, and the reward value of food. Appetite, BFDG Abstracts. 51, 752.
Mobbs, O., Crepin, C., Thiery, C., Golay, A., Van der Linden, M. (2010). Obesity and the four facets of impulsivity. Science Direct. 79(3):372-377.