Benefits of Intermittent Fasting: Weight Loss and More

Hunger is one of our basic physiological needs for survival. Nobody likes feeling hungry. Therefore, the idea of intentionally depriving oneself of food for some time with fasting or intermittent fasting is unfathomable for many. Unfortunately for a lot of us, eating has become a mere routine. Most individuals eat not because they feel the need but because they want to and can afford it. This attitude towards food leads to habitual cravings, malnutrition, obesity, and several chronic diseases. Reaching and maintaining a healthy weight has become a global concern that the seemingly forgotten practice of fasting has once again gained popularity and is now being tried by millions of weight watchers all over the globe. But what are the benefits of intermittent fasting? Is it just for weight loss?

What is intermittent fasting?

Strictly speaking, fasting per se is the complete abstinence of food and drinks often done for medical or spiritual purposes. On the other hand, intermittent fasting is a modified form wherein individuals still go on an extended period with little or no food intake but interspersed with periods of normal food intake. Intermittent fasting is sometimes referred to as caloric restriction, periodic fasting, total caloric desistance, or a method of energy deprivation.

The Muslim fast during Ramadan is a form of intermittent fasting. One eats breakfast before the first morning prayer (about an hour before sunrise) and then abstains from all food and drink until sunset that evening. The fast repeats the following day in the same way for an entire month. People with health issues, including pregnant and breastfeeding women, are not allowed to fast for Ramadan. The message we get from this is that using common sense when doing any kind of fast is paramount. Some health issues do well with some form of fasting, but the added stress makes them worse for others. So, consult with your health practitioner before embarking on a fast.

Due to the increasing popularity of this practice in recent decades, there have been numerous studies done to scientifically test the efficacy and benefits of intermittent fasting.

Aside from weight loss, intermittent fasting has been recommended for those who want to improve their brain, cardiovascular, and digestive health. The attributed health benefits of intermittent fasting dramatically improve metabolism, cellular health, and many other longevity markers.

How intermittent fasting works

There are complex mechanisms involved in intermittent fasting. When done correctly using scientifically-proven methods and coupled with caloric restriction, these are some of the many changes that may happen to the body:

Image credit: Mattson, M. P., Longo, V. D., & Harvie, M. (2017). Impact of intermittent fasting on health and disease processes. Ageing research reviews, 39, 46-58.
Increased:
  • cognition
  • neurogenesis
  • synaptic plasticity
  • heart rate variability
  • insulin sensitivity
  • ketone body production
  • fatty acid mobilization
  • parasympathetic tone
Reduced:
  • adipose mass
  • nutritional stress
  • inflammation
  • blood sugar levels
  • tissue damage
  • leptin
  • total cholesterol
  • markers of oxidative stress

 

Intermittent fasting may be difficult at first, especially for those used to the feeling of fullness all the time. However, our bodies are more intelligent and more adaptive than we think. As in times of food scarcity, our desire for food can be reduced and regulated. This form of adaptation enables us to eventually function at a high level even during a fasted state. Many people report increased concentration and productivity while fasting.

Types of intermittent fasting

There are different intermittent fasting variations which can last from 2 to as many as 21 or more days.

  1. Complete fasting every other day

An individual can abstain from all food and drinks (aside from water) every other day. In other words, alternate fasting and feasting.

  1. Partial fasting

This type of fasting can mean a lot of things. For some, this is synonymous with 70% calories restriction or consuming only 500-700 calories during the fasting period. For others, it is 2-5 days of water intake only. Some also do this by taking only one big meal a day (OMAD) and abstaining for the rest of the day.

  1. Time-restricted feeding (TRF)

Among the different types of intermittent fasting, this is probably the most popular one. TRF is also often called the 16:8 because it encourages eating meals within an 8-hour window (for example: 11 am to 7 pm) and fasting for 16 hours. Once the body is used to the 16-hour abstinence, it can be stretched to 18 hours without energy intake for optimum results.

Benefits of Intermittent Fasting and Keto Diet

Another popular weight loss regimen, Keto diet is different from intermittent fasting. However, these two have been proven to be effective for weight loss and energy stability when done hand in hand. This is because intermittent fasting with a high carbohydrate diet can cause unstable blood sugar levels, hunger pangs, sweet cravings, mood swings, brain fog, and low energy. The ketogenic diet, which limits carb intake but provides the necessary calories via increased (healthy) fat intake,

was originally designed to mimic the beneficial effects of fasting. A few studies attempt to compare the two to determine which one is better for weight loss, but because of the differences in their mechanisms, there is yet to be a conclusive report on which one should be favored by those who are watching their weight.

In the past, we have published a blog post about ketogenic diet (keto diet) and its implications, especially for gallbladder patients. If you want to learn more about ketosis, read our full blog entitled “Keto Diet for Weight Loss: Good or Bad for the Gallbladder Impaired”. One reminder though, is that the objective of intermittent fasting and Keto diet shouldn’t just be weight loss. Shedding off extra pounds should always be a secondary motivation to improving gallbladder and liver health by reducing inflammation, reducing stress, and supporting optimum nutrition.

6 Health Benefits of Intermittent Fasting

Intermittent fasting benefits:

  • support healthy weight loss and weight maintenance
  • improve cognitive performance
  • support cardiovascular health
  • help those with diabetes and insulin sensitivity
  • help reduce the risk of cancer
  • boost overall longevity

Intermittent Fasting and Weight Loss

Reducing food intake, either via intermittent fasting or caloric restriction, can help achieve and maintain the ideal weight for obese individuals. There are various mechanisms that explain why intermittent fasting promotes this effect:

  • Increased satiety and better control of appetite
  • Increased energy expenditure
  • Improved insulin sensitivity
  • Reduced inflammation

Oftentimes, we gain too much weight because of our hunger pangs and sweet cravings. To help prevent this from happening, intermittent fasting helps activate leptin and adiponectin, two hormones that are associated with appetite control and satiety. When fasting is done correctly and religiously, these hormones also help reduce the level of stress hormones and increase thyroid activity, which can result in increased energy expenditure. Circulating ketone levels are also elevated during fasting days. Because of this, the body remains burning fats instead of sugar. Proper intermittent fasting means not food binging during the periods of regular eating.

Insulin sensitivity is something that we will discuss more in the next section. We know for sure that blood sugar levels have a profound impact on overall weight and chronic obesity. They are also associated with inflammation that often leads to diabetic complications. As intermittent fasting works on these conditions, the stage is set for achieving and maintaining a healthy weight.

Intermittent Fasting Benefits on Mood and Brain Performance

Various studies have shown that intermittent fasting with caloric restriction is neuroprotective. It benefits the brain by reducing levels of oxidative stress and enhancing the resistance of cells against stress. Because of this effect, the development of various neurodegenerative diseases like Parkinson’s, Alzheimer’s, and Huntington’s are prevented. Intermittent fasting can also delay the onset and progression of cognitive degeneration. Lower calorie intake and periods of fasting may help improve memory, focus, and concentration.

Another effect of intermittent fasting is the improvement of mood and depression status. Based on a 2015 review of different behavioral experiments, it was shown that components of tension, anger, fatigue, and confusion improved due to caloric restriction and modified fasting. And although the introduction of a new eating regimen may be challenging to some, only about 15% of participants in these studies have reported adverse side effects like irritability, low energy, unmanageable hunger, and feeling cold.

Impact of Intermittent Fasting on Cardiovascular Health

Intermittent fasting and caloric restriction enhance cardiovascular function and improve several risk factors for coronary artery disease and stroke. LDL cholesterol is decreased while the highly-desired HDL cholesterol levels are increased among subjects. Caloric restriction reduces inflammatory processes that likely contribute to atherosclerosis. Experiments with animals maintained on an intermittent fasting regimen also exhibited increased resistance of heart cells to ischemic injury during myocardial infarction and stroke.

For those with a relatively healthy heart, intermittent fasting may still benefit their cardiovascular function since resting heart rate and blood pressure are positively impacted. It was shown that fasting individuals subjected to stress have a quicker recovery rate following removal of the stress source. Those who engage in sports or strenuous physical activity also have better cardiovascular function while on intermittent fasting.

How Intermittent Fasting Benefits Blood Sugar Levels

Intermittent fasting (IF) improves glucose regulation which induces the enhanced activity of serotonin (the happy hormone) and brain-derived neurotrophic factor (BDNF). BDNF helps keep normal glucose levels and regulates energy metabolism in the body. Aside from that, intermittent fasting shows variable effects on peripheral and hepatic insulin sensitivity.

The positive impact of IF on diabetic patients is also a commutative result of its effect on appetite and satiation, inflammation, cholesterol levels, and weight loss.

Intermittent Fasting and Cancer

A series of animal experiments have shown that periodic fasting lasting two or more days can be as effective as chemotherapy in delaying the progression of various types of cancers. Aside from that, it is also helpful for patients undergoing chemotherapy or radiation treatment as it helps protect normal cells from the toxic effects of such procedures while sensitizing cancer cells at the same time.

Aside from its protective and sensitizing impact on cells, a severely restricted diet that mimics partial fasting started at middle age causes a major reduction in tumor incidence, delays tumor onset, and reduces metastatic cancers.

Overall, intermittent fasting and caloric restriction reduce cancer risk due to the effect on a number of cancer risk biomarkers such as cytokines, insulin, and inflammation-related molecules like leptin and adiponectin.

Intermittent Fasting May Help You Live Longer

Experiments performed as far as 70 years ago showed that caloric restriction increases the lifespan of animal subjects like rodents and monkeys. More recent studies support this conclusion, adding that intermittent fasting benefits may include longevity, even when there is little decrease in caloric intake.

The beneficial effects of intermittent fasting and caloric restriction result from at least two mechanisms — reduced oxidative damage and increased resistance to cellular stress. Some tests show that the impact of these dietary regimens on the brain and cardiovascular system is similar to the effect of regular physical exercise.

As for our cells, tests on mice showed that intermittent fasting enhanced the survival of newly-generated neurons that arise from stem cells in the hippocampus. This means that the diet regimen enhances the plasticity of synapses and encourages cell regeneration.

Impact of Intermittent Fasting on Gallbladder and Gastrointestinal Patients

Before you jump on the bandwagon and start your intermittent fasting journey, it is always best to consult your medical practitioner. Having pre-existing health conditions may significantly alter or impact the effects of these dietary practices.

Research shows that intermittent fasting could increase stone formation by increasing the saturation of the bile with cholesterol for women (not men) who tend to form gallstones, but only during fasts of 10-15 hours. By 20 hours, the bile was no longer saturated. And in men, this didn’t happen at all. My advice for women doing IF of less than 20 hours would be to start every morning with a coffee enema to contract the gallbladder and flush any stagnant bile. This will also cause an increase of bile formation and secretion from the liver, thereby assisting with the removal of bile and cholesterol from the liver.
Also, longer fasts help to lower the saturation of bile. Based on the 20-hour finding and another study that took samples at 4,5 and 6 days of
fasting with a 30% reduction in bile saturation, it appears that a fast around 24-36 hours and longer would support the bile in not
forming stones.

Remember:

When doing intermittent fasting or any dietary change, it is important to think about your target and motivation. Is it just to lose weight? Maintain healthy cholesterol levels? Is it to prevent the aggravation of your condition? Or manage symptoms? Whatever it is, the right purpose is crucial.

Lastly, since intermittent fasting or caloric restriction means that you will still have periods of normal eating, you must eat right! Follow the gallbladder diet list to make sure that you are on the right track. Taking the necessary supplements may also help you achieve your desired health results.

 

References:

Halagappa, V. K. M., Guo, Z., Pearson, M., Matsuoka, Y., Cutler, R. G., LaFerla, F. M., & Mattson, M. P. (2007). Intermittent fasting and caloric restriction ameliorate age-related behavioral deficits in the triple-transgenic mouse model of Alzheimer’s disease. Neurobiology of disease, 26(1), 212-220.

Hartman, A. L., Zheng, X., Bergbower, E., Kennedy, M., & Hardwick, J. M. (2010). Seizure tests distinguish intermittent fasting from the ketogenic diet. Epilepsia, 51(8), 1395-1402.

Horne, B. D., Muhlestein, J. B., & Anderson, J. L. (2015). Health effects of intermittent fasting: hormesis or harm? A systematic review. The American journal of clinical nutrition, 102(2), 464-470.

Martin, B., Mattson, M. P., & Maudsley, S. (2006). Caloric restriction and intermittent fasting: two potential diets for successful brain aging. Ageing research reviews, 5(3), 332-353.

Mattson, M. P., & Wan, R. (2005). Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. The Journal of nutritional biochemistry, 16(3), 129-137.

Mattson, M. P., Longo, V. D., & Harvie, M. (2017). Impact of intermittent fasting on health and disease processes. Ageing research reviews, 39, 46-58.

Patterson, R. E., & Sears, D. D. (2017). Metabolic effects of intermittent fasting. Annual review of nutrition, 37.