EFFECTS OF FASTING ON FAT LOSS AND OVERALL HEALTH
When you hear the word ''fasting'', what is the first thing that comes to your mind? I bet you think of words such as''suffering'', ''starvation'', or ''stomach ache''. Well, fasting is everything but that.
Despite its recent popularity among celebrities and its growing buzz across social media, fasting has long been a common ancestral practice in many cultures throughout human history. While it was a tradition to honor their gods for some religious groups and societies, it was a kind of penance or punishment for others. Maybe that's why you thought of punishment!
Although it has been widely discussed, it wasn’t until a few years ago that science began to wrestle with all the difficult questions that come with the radical dietary choice - such as whether fasting was truly beneficial for weight loss and whether it could lead to long-term detrimental health conditions. In terms of potential health benefits, the answer is yes; it does bolster metabolic, cardiac, and intestinal health while fighting to reduce inflammation and some of the natural consequences of aging. Let's find out what this is all about.
Let's start from the beginning: What exactly is fasting?
Fasting is intentionally abstaining from eating and, sometimes, from drinking. From a purely physiological perspective, "fasting" can refer to the metabolic state you encounter when you have not eaten overnight or the state your body reaches after complete digestion and absorption of a meal.
Fasting and its recent popularity stems from the fact that every day, more and more people live with obesity, diabetes mellitus, and cancer. Obesity is now considered a pandemic disease, in which uncontrolled junk food intake and little physical exercise have created a health crisis across the world.. According to the World Health Organization, the proportion of the population considered to be obese is are expected to rise in the coming years.
Humans are mistakenly used to three meals a day: a breakfast, a hearty lunch, and a light dinner, or some combination of the three. However, such eating patterns often lead to metabolic imbalances such as insulin resistance or fat accumulation, especially when coupled with a sedentary lifestyle.
The daily dietary restriction that comes with fasting could play a key role in weight loss, which is also related to better health outcomes, including a reduction triglycerides and lower cholesterol levels.
Now, does fasting really mean you should stop eating entirely? No, because no one can live without consuming food from time to time. When we talk about fasting, we refer to dietary practices recommended by nutritionists and medical professionals such as alternate-day fasting, modified fasting regimens, and time-restricted feeding.
Ways to fast according to science
Alternate-day fasting means refraining from eating or drinking every other day. With this dietary regimen, some days are considered “no-calorie days,” s , while others are ad libitum (as you like it). This method has been studied extensively in laboratory settings and scientists have documented several metabolic benefits to fasting among animals when assessed against a control. However, it is not very suitable for humans in our day to day lives, since the overwhelming hunger during the days without food can be severely uncomfortable.
Modified fasting regimen
That said, science did not stand idly by and resign “fasting” to be a failure. Instead health professionals began to espouse diets that included small daily intakes of food to help alleviate the hunger pangs you would otherwise encounter during Alternate-Day Fasting strategies.. Still, during the days you set aside for fasting , you only ingest 20-25% of your energy needs. This is known as a modified fasting regimen and is one of the most commonly used.
Unlike alternate-day fasting, modified fasting has been widely practiced among individuals with documented success such as decreased weight, significant improvements in "bad" cholesterol, decreased inflammation-producing substances, even better mood and self confidence.
On the other hand, time-restricted feeding means you can only eat during a small window throughout the day, often ranging between 4 to 12 hours. . In this dieary regimen, you extend the overnight fast by skipping an early breakfast and instead limiting your intake to just lunch and dinner , thereby limiting food intake during certain times throughout the day as the name implies.
This is The Circadian Code's main point, by Satchin Panda, who claims that people improve their metabolic health when they eat in a daily span of eight to ten hours by eating the first bite in the morning the last in the evening.
What does fasting do for your health?
The benefits of fasting are rooted in the mechanics of metabolism, but to understand how it all works, we must first explore circadian rhythms and how they can impact our health.
The circadian rhythm is a natural process that occurs in our bodies to control the wake-sleep periods during a day. Simply put, it is a natural cycle of physical, mental, and behavioral changes that your body undergoes in a 24 hour period. That's why you feel tired, weak, or sleepy at night, while you have more energy and feel more productive during the day.
Circadian rhythms impact your metabolism throughout the day. For example, insulin sensitivity decreases during the evening due to its secretion rhythm. Thus, meals taken at night are linked with greater glucose and insulin exposure than those during the daytime.
It basically means that your body is made to eat during the day and not at night. When your body is aligned with its circadian rhythm,, it digests meals better and, in turn, works in balance with the rest of its functions.
With this in mind, let's talk about the benefits that fasting provides to you.
1. First things first: it can help you lose weight.
Your body needs energy for everything, which food provides it on a daily basis. However, when you skip a meal or attempt to fast , it looks for ways to acquire that energy from other sources, such as fats. Triglycerides (fats) are broken down into fatty acids and glycerol during the hours you spend fastingThey are consumed by your body as an energy supply,since they are not restored by food intake the overall of triglycerides in your system decreases.
At the same time, the liver turns fatty acids into ketone bodies, which represent a leading source of energy for many organs, especially the brain. By doing so, the whole fasting process breaks down fat for energy to allow you to live. Pretty impressive, right?
In this sense, many studies have shown that fasting reduces body weight in much the same way as a restrictive diet. One of these well known studies was conducted byKelsey Gabel and her colleagues from the University of Illinois, which confirmed that only eight hours of food restriction can positively induce weight reduction
2- Reduces risk of diabetes mellitus and improves glycemic control
We’ve talked about reducing overall intake of food, but it’s also important to understand that sometimes what matters is not just how much we eat, but when we eat that., Limiting food intake to daytime and avoiding those pesky late night snacks will not only allow your body to react better to meals, but it will be less exposed to glucose, so there will be less risk of insulin resistance and, ultimately, diabetes .
For example, one study proved that blood glucose remained stable while insulin was reduced, and pancreatic cell function improved in response to food. At the same time, insulin resistance was also reduced during five weeks of fasting. So limiting intake to certain times during the day could positively affect insulin levels throughout the body.
All these health parameters are crucial in the genesis of diabetes, and the more your health indices fall in line with standard baselines, the better. Undoubtedly, fasting seems an ideal preventative alternative for those with insulin resistance.
3- Gut health due to improvement of the gastrointestinal ecosystem
Did you know that your gut has trillions of bacteria? There are millions of germs inside your gastrointestinal tract that are essential for your body and its every day function.
Without bacteria, you would be exposed to many intestinal risks.These microbes act as a protective layer that shields you from dangerous germs, helps you metabolize and recover energy, and works to improve your intestinal barrier. Not to mention all the other benefits that a healthy gut can offer to your overall health.
This bacterial environment is called the gut microbiome, and the more diverse it is, the better for your health. This diversity is influenced by diet and circadian rhythm. Studies suggest that restrictive fasting and daytime food consumption can increase the diversity of intestinal germs and improve the gut's response to meals.
A case in point is the Weizmann Institute of Science study revealing that jet-lagged individuals have an increased risk of glucose intolerance and obesity due to changes in their gut microbiome.
The reason is that a bacterium, often referred to in studies surrounding obesity, called Firmicutes, curiously reproduces faster during jet lag than on non-jet-lagged days. This represents a heightened risk for obesity in people who often travel or eat after hours. Fortunately, this bacterial overgrowth is reversed once the circadian cycle is restored. Bet you didn't know that!
4- Reduces blood pressure.
It is no secret that blood pressure is one of the most unsteady health parameters (along with hormones, of course). Blood pressure changes even when you go from a sitting position to simply lying down, so you can imagine how much it can change before and after a meal.
These changes are influenced by both postural fluctuations and biological substances such as hormones, especially insulin.
Only five weeks of fasting with time-restricted eating can reduce blood pressure, mainly morning blood pressure.
According to experts, this could be the result of decreased insulin fluctuations tied to meals. In other words, the less you eat, the lower the meal-induced insulin spikes. Since these spikes can increase blood pressure, the less you eat, the lower your post-meal increase in blood pressure
5- Makes you live longer as it reduces free radicals and aging genes in the long run.
This part’s tricky, so we’ll break it down slowly
Your body is designed to age because as it functions, it produces toxic substances called reactive oxygen species (free radicals). Fortunately, it has a trick up its sleeve. It uses a defense mechanism called the antioxidant system, which is responsible for reducing the effects of reactive oxygen species on your cells and moderating the effects of aging.
Sometimes free radicals can overwhelm your antioxidant system due to exposure to pollutants, unhealthy lifestyles, or illness, leading to oxidative stress that makes you age quickly..
What role does fasting play here? Fasting hours have been found to protect against aging by transiently increasing cellular reactive oxygen species, which triggers a protective and adaptive response.
Over time, it acts as a defense mechanism that ''trains'' cells to protect themselves from further aggression by free radicals.
According to a University of Florida study, the primary gene for this protective response is SIRT3, expressed during fasting in the mitochondria (the cell's motor)
A word from Layvela
Fasting comes in many types depending on each body's needs, ranging from food restriction to alternate day intake. However, under the right circumstances, it is undoubtedly an effective way of improving health..
In addition to fasting, healthcare professionals recommend that you consume a nutritionally balanced diet if you really want a healthy lifestyle. This includes foods with more nutrients than calories (although they are still essential), and have a balanced intake tailored to your needs each day. Everybody is different, so each diet and fasting regimen varies from person to person.
Moreover, not all bodies are used to fasting, so not everyone can go about itin the same way. If you are really thinking about fasting, a nutritionist can help you find the best dietary regimen to pursue according to your own pace and metabolic needs.
1- Obesity and overweight [Internet]. Who.int. [cited 2021 Oct 20]. Available from: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
2- Ganesan K, Habboush Y, Sultan S. Intermittent fasting: The choice for a healthier lifestyle. Cureus [Internet]. 2018; Available from: http://dx.doi.org/10.7759/cureus.2947
3- Patterson RE, Sears DD. Metabolic effects of intermittent fasting. Annu Rev Nutr. 2017;37:371–93.
4- Antoni R, Johnston KL, Collins AL, Robertson MD. Effects of intermittent fasting on glucose and lipid metabolism. Proc Nutr Soc. 2017;76(3):361–8.
5- Sutton EF, Beyl R, Early KS, Cefalu WT, Ravussin E, Peterson CM. Early time-restricted feeding improves insulin sensitivity, blood pressure, and oxidative stress even without weight loss in men with prediabetes. Cell Metab. 2018;27(6):1212-1221.e3.
6- Gabel K, Hoddy KK, Haggerty N, Song J, Kroeger CM, Trepanowski JF, et al. Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutr Healthy Aging. 2018;4(4):345–53.
7- Gibbs M, Harrington D, Starkey S, Williams P, Hampton S. Diurnal postprandial responses to low and high glycaemic index mixed meals. Clin Nutr. 2014;33(5):889–94.
8- Thaiss CA, Zeevi D, Levy M, Zilberman-Schapira G, Suez J, Tengeler AC, et al. Transkingdom control of microbiota diurnal oscillations promotes metabolic homeostasis. Cell. 2014;159(3):514–29.
9- Persson SU. Blood pressure reactions to insulin treatment in patients with type 2 diabetes. Int J Angiol. 2007 Winter;16(4):135–8.
10- Wegman MP, Guo MH, Bennion DM, Shankar MN, Chrzanowski SM, Goldberg LA, et al. Practicality of intermittent fasting in humans and its effect on oxidative stress and genes related to aging and metabolism. Rejuvenation Res. 2015;18(2):162–72.
11- Tilg H, Kaser A. Gut microbiome, obesity, and metabolic dysfunction. J Clin Invest. 2011;121(6):2126–32.