‘Pie hole’, colloquial for one’s mouth, is believed to have evolved in the USA in the 1980s from the British expression ‘cake hole’ (coined in the mid 20th century). Pie hole refers to a mouth, as in: Shut your pie hole or, in this case: Put less in your pie hole.

Wednesday, July 25, 2018

Are You Into Intermittent Fasting?

Intermittent fasting is a hot-button topic, and a popular trend in the weight-loss arena. A recent study shed some light on the science and efficacy of such a dietary pattern. So, should you fastidiously fast the fat away?

As usual, there's more to the story than the click-baity article titles fooling you with follies for fast fat loss.

Intermittent fasting is a broad term covering diets including: 
  • Start-stop eating where people fast completely for 24 hours once or twice a week
  • The 5:2 diet where participants choose one or two non-consecutive days and consume only ~500kcals on those days and eat normally on the other days
  • The 16/8 pattern where people eat only during an 8 hour window, the other 16 hours are fasted
This last pattern involving the 8 hour eating window is where we'll wander today.

A new study found that participants who followed this eating pattern for 12 weeks had the following results compared to those following their usual diets:
  • An approximate 3% loss of body weight
  • An approximate kcal deficit of 300kcal per day (hence the above weight loss)
  • Participants reduced their eating window on average by 3 hours (from 11 to 8 hours)
    • Though research shows only 15% of adults have an eating window <12 hours 
  • A significant decrease in systolic blood pressure 
A few other noteworthy mentions:
  • This study was performed with an obese population
    • Meaning results are not applicable to other populations (eg: normal-weight or overweight individuals) without more research
  • This diet pattern involved no calorie counting
    • A great thing considering counting calories is often inaccurate, time-consuming, not sustainable for a long period, and creates a preoccupation with food
  • The feeding window in this study was 10am-6pm
  • Participant adherence to this eating pattern was positive
    • Meaning this type of dietary pattern shows promise of being sustainable over a long period, compared to alternate-day fasting (like 5:2), or ridiculous diets like "no sugar" or "no chocolate" that cause rebound-like effects when dieters inevitably "fall off the wagon"
  • Compared to other forms of intermittent fasting, this period of time restriction produced a lower energy deficit (meaning less weight was lost) 
    • For example: emerging evidence shows alternate-day fasting produces a deficit of 25-30% of daily calories compared to the time-restricted window that produced ~20% deficit
    • The likely reason is that alternate-day fasting requires strict monitoring and calorie counting where time-restricted fasting does not, as the saying goes "work smarter, not harder"
  • Other cardiometabolic factors (eg: glucose control, insulin sensitivity, triglycerides, cholesterol levels) didn't reach statistically significant levels of improvement 
    • However, the obese population studied had baseline cardiometabolic markers within normal ranges. Therefore, it's quite possible that repeating this study in obese people whose markers are abnormal would see improvement
Lastly, we can't have a conversation about time-restricted eating, as exhibited in this study without mentioning the body clock (circadian rhythm). A previous Pie Hole article details the research on our internal rhythm and how it is impacted by the time of day we eat, drink, and sleep. The timing of food has flow-on effects that can alter metabolism and the microbiome. Research shows a shorter eating window (of <12 hours) helps improve sleep quality, weight loss, weight maintenance, and energy levels.

What are the take home messages?
  1. Shortening your eating window to <12 hours can have many health benefits including higher sleep quality, this in turn impacts metabolism and hormones related to hunger, thus weight
  2. Shortening your eating window is sustainable:
    • It doesn't require calorie counting or strict "dieting" which can lead to a preoccupation with food, increase the risk of disordered eating, and lead to weight regain
    • Long term sustainability means greater adherence to the eating pattern, less "falling off the bandwagon", more positive and long term results 
  3. Put less in your pie hole during a window of 12 (or less) hours per day