Monday, October 8, 2007

Intermittent Fasting - Research update

We have discussed intermittent fasting (IF) before and I listed some useful resources in a posting here, including books you could read. (If you want an ebook there are two recommendations: a free one Fast5 or one you will have to buy - but it is worth it for the additional material - Eat Stop Eat)

New Research

Anyway, I just wanted to highlight a couple of other studies that have either recently been published or have recently come to my attention regarding this way of eating.

Firstly one about Ramadan fasting - a basic IF regime:

Our study findings indicated Ramadan fasting affected body weight, BMI, body water percentage and body fat percentage (they got leaner!). Interestingly, these changes were effected
despite insignificant changes in energy and macronutrient intake.

Abstract / Full Text

Body composition, nutrient intake and physical activity patterns in young women during Ramadan.

INTRODUCTION: Muslims abstain from food and fluid between the hours of sunrise to sunset, and usually eat a large meal after sunset and a lighter meal before sunrise. The purpose of this study was to assess body composition, nutrient intake and physical activity patterns during Ramadan fasting.
METHODS: This study was carried out during Ramadan in October 2004. A total of 57 female subjects were recruited from The Hashemite University in Jordan. Body weight, fat percentage, muscle mass, and percentage body water content were measured, and body mass index (BMI) was calculated. Estimated food records over a duration of three days were used to assess the intake of energy, carbohydrates, protein, fat, and sugars before and during Ramadan fasting. Physical activity patterns were determined from a three-day activity diary before and during Ramadan fasting; the amount of physical activity was expressed as the physical activity level.
RESULTS: Body weight and BMI decreased significantly during Ramadan fasting. The mean energy and nutrients intake before Ramadan (energy; percent carbohydrates:protein:fat was 1,252; 56:12:33) and during Ramadan (1,171; 56:13:34) were not significantly different. The mean physical activity level was 1.54 before Ramadan and 1.51 during Ramadan, and this was also not significantly different.
CONCLUSION: This study revealed that there was a significant weight loss during Ramadan. Estimates of energy, carbohydrates, protein, fat and sugar did not change, despite the reduction in the number of meals taken. The overall activity patterns remained similar.


The other one is a bit older(published April 1 2007)Again note that IF led to significant decreases in body fat....

A Controlled Trial of Reduced Meal Frequency without Caloric Restriction in Healthy, Normal Weight Middle-Aged Men and Women

Interpretive Summary
: Although three meals per day support rapid growth in children, it may not be the healthiest eating pattern for adults. The rising obesity epidemic usually occurs among individuals consuming several large meals per day. Overeating is widely accepted as a cause of premature death from cardiovascular disease and diabetes, but few studies have determined how meal frequency affects health risk. Despite a general perception among the public that it is important to eat three or more meals per day, there have been no controlled research studies that directly compare the effects of different meal frequencies on human health. A pilot study was conducted to determine the feasibility of controlled meal frequency in normal weight, middle-aged men and women. Participants consumed all of their required calories either in one meal per day or three meals per day for eight weeks. Results showed that the majority of the study participants were able to consume total calories in one meal per day. Consumption of one meal per day versus three meals per day increased the participants' blood pressure but had no effect on heart rate, body temperature and the majority of blood tests measured. Scientists and nutritionists interested in the effects of eating patterns that may influence health may find this information useful.

Technical Abstract: Background: Although consumption of three meals per day is the most common pattern of eating in industrialized countries, a scientific rationale for this meal frequency in regards to optimal health is lacking. A reduced meal frequency diet can improve health and extend lifespan of laboratory animals, but its effect on humans has never been tested.
Objective: A pilot study was conducted to establish the effects of a reduced meal frequency diet, without an overall decrease in energy intake, on a range of health indicators in normal weight healthy male and female subjects.
Design: The study was a randomized cross-over design, with 2 eight-week treatment periods. During the 8 week treatment periods, subjects consumed all of their calories for weight maintenance distributed in either 3 meals/d (control diet) or 1 meal/d (experimental diet).
Results: Subjects who completed the study maintained their body weight within 2 kg of their initial weight throughout the 6 month period. There were no significant effects of meal frequency on heart rate, body temperature and the majority of blood variables measured. However, when on 1 meal/d, subjects exhibited: a significant increase in hunger; a significant modification of body composition with reductions of fat mass; significant increases in blood pressure and levels of total and LDL and HDL cholesterol; and significant decreases in levels of triacylglycerol and cortisol.
Conclusions: Normal weight subjects are able to comply with a 1 meal/d diet. When meal frequency is decreased without a decrease in overall calorie intake, there are modest changes in body composition, some cardiovascular risk factors, and hematological variables; some of the changes are suggestive of poorer health, while others are suggestive of improved health.

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