Updated: Sep 23, 2019
What is the deal with intermittent fasting and can it really help with weight loss, energy, blood sugar balance, thyroid health, etc. Here is a Registered Dietitian's review on what intermittent fasting is and how it can benefit health.
What is Intermittent Fasting?
To put it simply and take away the intimidation factor, we all practice intermittent fasting - when we sleep. If you slept 8 hours last night, that was 8 hours you weren't consuming any food or beverage. Intermittent fasting is a conscious approach to shortening the window of eating to the most optimal time for your body. Intermittent does (and should) vary for each individual.
Intermittent fasting can vary in length, but it is a designated time frame for consuming calories. Strict intermittent fasting can mean only eating for 6 hours out of the entire 24-hour day. Or, it can be as broad as eating within a twelve hour period. I have found a nice average for maintenance and health prevention is a ten hour window of eating, which results in a 14-hour fast.
If you wake at 6 am you can drink as much water as you'd like. You can even a cup of tea or coffee (black). But wait until you are hungry to eat your first meal.
Take note of what time you notice hunger hit. Is it an hour later, at 7 am? Or is it not until 10 am? This will help you to determine when your window of eating should start. For me, it is 8 am.
Now when you have your first meal you are breaking your fast...aka BREAKFAST
Start your ten hour window of eating from now. Since I start eating at 8 am, my ten hour window goes until 6 pm. Now am I always able to eat before or at 6 pm? No, there is a day here or there where I cannot eat dinner until 7 pm but since my body is accustomed to eating earlier I am usually past hungry and can have a smaller dinner those nights.
You want to always give yourself 3 hours before bed that you do not eat or drink anything besides water. This allows for your body to digest before sleep.
It is also why I recommend eating every 4 hours so that your body has time to fully digest the food you had from your last meal. In most countries there is no such thing as snacking, so your ultimate goal is to eat enough calories and variety to be satisfied for 4 hours until your next meal. If you are physically hungry, think of a snack as a mini-meal and choose a balance of protein, carb and fat.
An example of a balanced and satisfying snack would be an Apple + 2 Tbsp. Almond Butter. The apple provides carbohydrates and fiber, while the almond butter provides protein and healthy fat.
What are the proven health benefits of intermittent fasting?
There are many studies and research pointing to health benefits of fasting; such as weight loss, decreased cholesterol, balanced blood sugars, and increased energy.
Ever wonder why you need to fast for 12 hours before having your annual blood sample drawn? It is because we know that fasting for 12 hours will allow our bodies to achieve a steady-state for metabolic substrates like lipids and blood sugar, as well as hormones such as estrogen and insulin. Wouldn't you like your body to achieve a steady state of metabolism and hormones on a daily basis?
Research is still in its early stages and results are limited in human clinical studies. There are many beneficial studies reported in mice, but we do need to keep in mind that human studies are small and selective.
Weight Management and Appetite Control. "A study in 8 overweight young adults found that increasing the nightly fasting duration to ≥14 hours resulted in statistically significant decreases in energy intake and weight, as well as improvements in self-reported sleep satisfaction, satiety at bedtime, and energy levels (1).
Meta Analysis of Weight Management. "It appears that almost any intermittent fasting regimen can result in some weight loss. Among the 16 intervention trials included in this review, 11 reported statistically significant weight loss." (2).
Blood sugar and insulin regulation has been reported in alternate day fasting, which is having days of low calorie (less than 800 calories/day) alternating with full calorie days dependent on your body's calorie needs. Remember that insulin is a hormone, and adequate sleep is also an important factor in regulating hormone production.
Intermittent does (and should) vary for each individual. Working with a dietitian or other credentialed health professional will help you to determine a safe and effective eating pattern for your health and lifestyle.
Work with a dietitian to manage a safe and healthy fasting lifestyle for your health. It is important to not restrict yourself to a point where disordered eating can occur, such as bingeing.
If you'd like to work with me, or you have questions on this article feel free to reach out to me at firstname.lastname@example.org
Stay Healthy, Happy & Comfortable!
Liz Riesen, RD