Intermittent Fasting 2-days vs. 1-day Per Week Increases Weight Loss In Overweight Men and Women
Given the same energy intake and expenditure, intermittent fasting two days versus one day per week increases weight loss in overweight men and women
Intermittent fasting is becoming more and more popular and is seen as an effective dietary strategy for weight loss.
Of all the different types of intermittent fasting, several are particularly common and have shown efficacy in weight loss and health improvement, some of which include:
- Periodic intermittent fasting includes fasting one to two days/week while eating freely for the remaining five or six days.
- Alternate day fasting, consisting of no – or very low – calorie intake every second day while eating freely the other days
- Time-restricted eating, consisting of fasting for 12–20 hours/day while the remaining time eating freely
The reason why intermittent fasting works is that it is associated with increased oxidation of fatty acids (lipolysis) and ketone body formation (ketogenesis), activated cell-signaling pathways (insulin sensitivity, reduced inflammation, autophagy), and preservation of lean body mass, known as “metabolic switching”.
The interesting fact however is that typically, these mechanisms are not fully activated until at least 24 hours of fasting.
In a recent study published in the Nutrition Journal, a group of 20 participants, all of whom were either sedentary or lightly active (under 30 minutes, two days/week of organized physical activity), overweight or obese (with a BMI of over 27.5 and a body fat percentage over 30), weight
stable, and middle-aged (30–65 years), were invited to participate in the study.
The 20 study participants were then randomly assigned to either: a) an intermittent fasting diet for one day/week (Intermittent fasting of 36 hours in total) and protein pacing diet for the remaining six days/week (Protein pacing refers to 4–6 meals/day evenly-spaced, where each meal contains 25–40g of protein), or b) an intermittent fasting diet for two consecutive days (intermittent fasting of 60 hours in total) and protein pacing diet for the remaining five days/week for four weeks.
During fasting days, participants fasting for one day/week were allowed to consume 400 Kcal/day, while participants fasting for two consecutive days were allowed 500 Kcal/day. During non-fasting days the dietary regimen provided 1350 and 1700 kcals/day for women and men, respectively, and a macronutrient distribution consisting of 35% protein, 35% carbohydrate, and 30% fat.
The results after the four weeks show that participants who fasted for 2 consecutive days resulted in greater body weight and waist circumference loss compared to participants who only fasted for one day, 7.1kg and 4.7kg, or 7% and 5.2% of body weight from baseline, respectively. Similarly, participants reduced waist circumference by 7.6cm and 5cm or 8% and 4.8% from baseline, respectively.
As the authors suggest, this study supports the combination of intermittent fasting and protein pacing as an effective short-term nutritional intervention for weight loss.