In last month's newsletter I reviewed: What is the healthiest food consumption? Our plate should contain lots of veggies, fruits, nuts, seeds, and some healthy grains (gluten free for some). What about meat? I am not a vegetarian or vegan. But, I don't eat as much meat as I used to and always go for the lean meats. No processed meats. Sandwiches are a rarity for me and my husband.
Now let's discuss the controversial topics of: How often and when should we eat? I would like to review the data on FASTING. While there is no shortage of information on the topic, there is a shortage of scientific support. And, most of the data is in animals, specifically rodents. This newsletter is a summary of an article published last year by two expert doctors at the University of California who reviewed the world's literature on Metabolic Effects of Intermittent Fasting published in Annual Review of Nutrition 2017.
What is FASTING?
The types of fasting vary tremendously. There are extreme types of fasting for days, even weeks, with nothing consumed except large amounts of water. While this has been promoted as a treatment for numerous diverse health disorders, it is extreme, must be medically supervised, and has no prospective, comparative data to support it. While Jesus did it for 40 days, I don't recommend it for us unless future compiling evidence-based data says we should. The other types of fasting vary from skipping meals and eating only twice a day to not eating for a whole day.
Alternate Day Fasting
: Periodically not eating any food at all for a whole day followed by routine eating days is associated with weight loss but most find this not acceptable because of reports of extreme hunger during fasting days.
Modified Fasting Regimens
: In this regimen, fasting days are periods of severely limited food intake rather than no food intake. Food (energy) consumption is limited to about 25% of energy needs on fasting days with regular eating on the other days. An example is the 5:2 diet which involves food restriction on 2 nonconsecutive days a week with regular eating during the other 5 days. The authors of studies on this regimen unanimously report that the overall metabolic benefits of these type fasting regimens are not superior to those that simply reduce energy (food) restriction on a daily basis. In other words, cutting down on the calories consumed every day is just as good as extreme reductions only on some days.
: This form of fasting involves prolonging the duration of nighttime fasting. Most data are derived from rodent studies with daily fasting intervals of 12 to 21 hours. Overall, these studies reveal reductions in body weight, cholesterol, triglycerides, glucose, insulin, and inflammatory markers.
In humans, prolonging the duration of nighttime fasting has been shown to improve weight loss. There are many studies of religious fasting. It is an Islamic practice among healthy Muslins to have no food consumption from sunrise to sunset during the holy month of Ramadan. This has been associated with weight loss. Many Seventh-day Adventists adhere to a two meals per day pattern often consuming the last meal in the afternoon, which results in a prolonged nightly fasting period. The authors of the review article state that Seventh-day Adventists "live approximately 7.3 years longer than other white adults." They attribute this primarily "to their healthful lifestyle, including not smoking, eating a plant-based diet, and exercising regularly." Sounds like they are Living WELL Aware!
The authors go on to state that many studies support improved health and lower weight with prolonging the time during which little or no food intake occurs in the evening and during the nighttime. Data from the CDC National Health and Nutrition Examination Surveys (NHANES) showed improved glucose levels and lower markers of inflammation with each 3-hour increase in nighttime fasting duration.
What about data on cancer?
The authors evaluated nightly fasting interval in 2,337 breast cancer survivors in the Women's Healthy Eating and Living (WHEL) Study. This study is the first to reveal a link between extending the nighttime fast to > 13 hours and improved health outcomes including less chance of cancer recurrence. This prospective 7-year study concluded that women who fasted < 13 hours per night had an increased risk of cancer recurrence, higher glucose levels, and shorter sleep duration.
How does intermittent fasting lead to improved health outcomes?
It is hypothesized that intermittent fasting regimens influence our metabolism through effects on the circadian rhythm (our day/night biologic clock), the gut microbiome (bacteria) and modifying our lifestyle. Consuming food outside the normal phase (i.e. late-night eating in humans) may reset our biological clocks and disrupt energy balance. Many studies document shift-work disrupts circadian rhythms and is associated with diabetes, obesity, cardiovascular disease, and cancer (particularly breast cancer). Meals consumed at night are associated with higher glucose and insulin levels leading to increased diabetes over time.
The authors declare the scientific data "strongly suggest that the timing of food intake is an important determinant of human health and disease risk." They also assert that "intermittent fasting regimens are not harmful physically or mentally (in terms of mood) in healthy, normal weight, overweight, or obese adults." Although not mentioned by the authors, I would like to personally add my recommendation that if someone is diabetic, especially with difficulties in blood sugar extremes, they consult with their healthcare provider about prolonging the nighttime fasting interval.
The Bottom Line
: Not only WHAT we eat, but HOW OFTEN and WHEN we eat appear to influence many of our metabolic functions and health. As I reviewed the data on fasting, I thought about growing up on the farm. We ate dinner at around 6pm and ate nothing after that. There was no nighttime eating. After reviewing the potential benefits on extending the nighttime fasting interval, I tried it myself. I stopped all eating after dinner (no nighttime snacks) and made it a goal to not eat dinner late. I also occasionally delayed breakfast by making myself a protein shake and drinking it later in the morning. The result: I felt great and found I didn't consume more calories when I did eat. It was easier for me to maintain to weight at the desired goal.
Assess what you eat. Do you need to cut back on food and drinks that are calorie rich and nutrient poor? Assess when you eat. Do you often eat dinner later and or have nighttime snacks? Simply tweaking your dietary habits slowly over time can lead to major weight loss and or improved health outcomes including reduced risk for cancer. It's about Living WELL Aware!