There are many health benefits to intermittent fasting. The type discussed in this article is the 16:8 and 18:6 styles of intermittent fasting. Benefits range from better gut health and disease prevention, to slowing down the aging process.
The information presented here is not medical advice.
Contents
What is 16:8 and 18:6 fasting?
For 16:8 intermittent fasting, every day across 24 hours, you can only eat for 8 hours out of those 24 hours. The remaining consecutive 16 hours is fasted.
For 18:6 you can only eat for a set 6 hours in a day, which is then followed by a consecutive 18 hours of not eating. It's easier to start with 16:8, but 18:6 may be more beneficial with more time spent in a low insulin state. [8]
When should I eat when intermittent fasting?
This depends on your lifestyle. Most people already skip breakfast. A common eating period for those intermittent fasting is from 12pm midday, so lunch will be the first meal of your day, And then having your last meal at 6pm for 18:6 fasting, or 8pm for 16:8 fasting.
How many calories should you eat during intermittent fasting?
A standard daily calorie intake, disregarding an individual's specific weight, height, or metabolism, is 2000 calories (8400 kilojoules) for women, and 2500 calories (10500 kilojoules) for men.
Your calorie intake should reflect your weight gain or weight loss goals. That is independent of whether or not you're intermittent fasting. You should be hitting your calorie intake goals in your 6 or 8 hour eating window, as if you weren't intermittent fasting. It's easier to eat less during fasting since you may not be able to consume your regular amounts in a shorter time span.
The important this is to try to hit your macronutrient goals for the day with your planned food intake, without resorting to unhealthy snacks.
Reducing your daily calorie intake is not mandatory. You can still eat the same amount of calories, you just have to shorten your eating window for the day. Those trying to gain muscle mass shouldn't reduce their calorie intake.
Though there can be benefits to those that are trying to lose weight, in that you might not feel as hungry while intermittent fasting. [7] If you're eating a good amount of protein and slow-release carbohydrates, you may subsequently end up eating less calories throughout the day.
Can you eat anything while intermittent fasting?
You can't eat any solid food during your fasting period, or anything that has calories. Here's what you can drink:
- Plain water
- Natural loose leaf teas with no additives
- Black coffee with no additives
Image courtesy of Julia Sakelli.
Feeling Hungry During Intermittent Fasting
The first thing to do is to make sure you're drinking water so that you're not getting dehydrated, and mistaking your body's need for water as hunger.
Secondly, you should eating the same amount of food you were eating before you were fasting. The only way to accurately do this is by calorie counting your meals, or ensuring you're measuring the quantity of food entering your body another way. It's very easy to eat less in a day, when you're only allowing yourself to eat in a small 6 or 8 hour window.
Thirdly, your body may still be adjusting to your intermittent fasting routine. Depending on the person, this could take a few days, to up to 2 to 4 weeks. Protein takes longer for your body to process than carbohydrates, so increasing protein intake during your eating hours can allow you to feel less hungry for the day.
Benefits of Intermittent Fasting
Burning Fat
When your body is in a fasted state, your liver will break down fats and produce ketones that your body will use for energy. This is triggered by reduced hormone insulin that is required to turn sugar into energy. [2]
Feeling Less Hungry
Ghrelin is a peptide, a building block of proteins, that makes you feel hungry. While leptin is a hormone that makes you feel full.
Ghrelin is produced in the stomach when you're low on energy, and leptin is produced by body fat. Intermittent fasting may lead to decreased ghrelin levels, lowering the desire to eat. [7]
Image courtesy of Pixabay.
Improved General Health
Your body is better protected from diseases by improved cell renewal. Autophagy is a process where cells in the body clean themselves, removing the parts of itself that can cause disease, including: misfolded proteins, damaged organelles, and pathogens. [9] Food deprivation by fasting causes, causes autophagy. [10] Although the main benefits may only be reaped after 18 hours of fasting, promoting lower insulin levels by exercising and reducing carbohydrates in your diet could trigger autophagy earlier. [8]
Brain Disease Protection
The hippocampus is the part of the brain that is important for memory and learning. During metabolic stress, caused by fasting, there is increased mitochondria in the hippocampus used to generate energy for brain cells. Being in a fasted state may help prevent age-related brain diseases that cause cognitive dysfunction and memory loss. [5] And it has been shown that it does lead to cognitive improvements in patients suffering from Alzheimer's disease. [6]
Cancer Prevention
Autophagy may help prevent the initiation of cancer by preventing chronic tissue damage and cell death. [13] But for someone that already has cancer, intermittent fasting may not be ideal. [13] [14]
Look Younger, Feel Younger, Live Longer
DNA damage contributes to aging, and occurences of it increases with time. Sirtuin proteins are essential for DNA repair, and the levels of sirtuins in the body increases with calorie restrictions (from fasting, and eating less), as well as with regular exercise and a healthy diet. [12] Higher levels of sirtuins, mTOR, AMPK can help the body fight age-related, and genetic diseases. [11]
Image courtesy of Andrea Piacquadio.
Lower Cholesterol Levels
Despite what may be a temporary increase in cholesterol due to LDL being mobilised to distribute energy from fat, [3] overall you may see a drop in LDL (bad cholesterol) levels relative to HDL (good cholesterol). [4]
References
[1] National Library of Medicine, 2013. Roger Collier.
[2] What are Ketones and Their Tests, 2020. Dr Michael Dansinger.
[3] Why do you get High Cholesterol After Intermittent Fasting, 2019. Dr Eric Berg.
[4] Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study, 2012. Nematy, Alinezhad-Namaghi, et al.
[5] The fat-fueled brain: unnatural or advantageous, 2013. Shelly Fan.
[6] Effects of Ketone Bodies on Brain Metabolism and Function in Neurodegenerative Diseases, 2020. Jensen, Wodschow, et al.
[7] Early Time-Restricted Feeding Reduces Appetite and Increases Fat Oxidation But Does Not Affect Energy Expenditure in Humans, 2019. Ravussin, Beyl, et al.
[8] The Sweet Spot for Intermittent Fasting, 2016. P D Mangan.
[9] Autophagy: cellular and molecular mechanisms, 2010. Glick, Barth, et al.
[10] The effect of fasting or calorie restriction on autophagy induction: A review of the literature, 2018. Bagherniya, Butler, et al.
[11] David Sinclair: How to Change Your Diet to Live Longer, 2022. Daniel R Miranda.
[12] Sirtuins, a promising target in slowing down the ageing process, 2017. Grabowska, Sikora, et al.
[13] Role of autophagy in cancer prevention, 2012. Chen, White.
[14] Autophagy and autophagy-related proteins in cancer, 2020. Li, He, et al.
No comments:
Post a Comment