What is Intermittent Fasting?

The overall epidemiology of obesity is escalating at a rate higher than ever before. The predisposition of obesity into other complications such as diabetes, coronary diseases, and overall impact on the quality of life is a significant concern these days.[1] Considering the menace and its long term impacts, the weight management systems are also gaining a lot of importance. 


The concept of intermittent fasting, which refers to alternate periods of diet and fasting, is gaining a lot of importance these days. It enhances the glucose and lipid homeostasis in the body, which helps in weight management and overall enhancement of metabolic health. Intermittent energy restriction and time-restricted feeding are the two subset approaches of intermittent fasting. The whole idea behind the entire concept is to establish a pattern of energy restriction and altering the timings for the intake of food resulting in periods of frequent periods of fasting.[2]

How does Intermittent Fasting work?

Intermittent Fasting Diet Plan vs. Calorie Restriction Diet Plan

The traditional calorie restriction diet plan has been in use for ages. By restricting the calorie, intake weight management is beneficial in terms of increased insulin sensitivity, resistance to stress, and an overall increase of life span.[3 ]

However, it is quite challenging to abide by this plan. The chances of overeating low-calorie food products and the threat of cheat meals are significant challenges while committing to low-calorie diet plan.[4]

In contrast, patients show wider acceptability to the intermittent fasting diet plans. Also, based on the studies conducted, the effectiveness of intermittent fasting exceeded those of caloric restriction.[3]

Benefits Of Intermittent Fasting

There are several benefits that have been supported by studies:

1. Weight loss: Diet plans generally aim at weight management or weight loss. Following any intermittent fasting, plans help in shedding the extra kilos. Research studies conducted on subjects for two weeks reflected a weight down rate of 1.3%. Also, the rate was observed as 8% for the eight-week trial.[5] 

However, an extended trial was conducted for one year in 2017 to compare the benefits of intermittent fasting and the traditional calorie restriction diet plan. The studies revealed no such difference with, and both methods had similar effects. However, acceptance for intermittent fasting was higher than the calorie restriction plan.[6]

2. Cardiac health benefits: Benefits of intermittent fasting in promoting cardiac health by preventing heart diseases are highly substantial. A study conducted on subjects for a span of 2 months revealed a reduction in the heart rate. Also, the level of circulating glucose, insulin, and homocysteine dropped down. All these factors contribute to minimizing the risk of heart diseases. In another two-month-long study impact of alternate-day fasting, plan was studied. A drop in fat mass, LDL cholesterol level, and triglyceride concentration further supported the claim of the initial study and proved the benefits of the intermittent day fasting in improving cardiac health.[7]

3. Brain health benefits: Benefits of intermittent fasting for effects on brain health have been conducted only in animal models. However, the results reveal an excellent prospect for similar effects in human beings as well. Intermittent fasting reduces inflammation in the brain, which is one of the primary reasons behind diseases linked to the mind. This is due to the changes induced in the hippocampus pertaining to the effect of the sodium-potassium channel and oxidative status caused by the polysaccharides.[8]

4. Cancer protection: Researches are conducted to study the impact of various diet plans and their benefits in terms of protection against cancer. To evaluate the benefit of intermittent fasting diet plan in cancer protection, multiple studies were conducted on animal models. The results have shown a positive outcome in terms of decreasing the development of lymphoma, limiting the tumor survival rate, and also slowing the rate of spread of cancer cells. Thus, the intermittent diet plan can help in minimizing the risk of cancer. More elaborate studies are required to evaluate the efficacy of human beings.[9]

5. Improved cell turnover rate: Autophagy or cell death is an essential process in the body to get rid of the damaged cells and carry out detoxification. Intermittent fasting supports this process of detox. LC3A gene and the mTOR protein regulate the process of autophagy in our body. Intermittent fasting plan involving diet restriction from 8:00 am to 2:00 pm enhances the functioning of LC3A and MTOR protein. Thus, accelerating the process of detoxification.[10] Therefore, intermittent fasting can be very instrumental in improving the cell turnover rate of the body. This can help in slowing down the process of aging and also contribute to increased immunity.

Precautions with Intermittent Fasting

Side Effects

Studies investigating the advantages of intermittent fasting point to certain side effects that may occur during the fasting phase of the eating plan. For example, it's quite common to feel moody, tired, and experience headaches as soon as your calories are seriously restricted.[11]

Reduced Physical Activity

A notable side effect of intermittent fasting might be the decrease in exercise or physical activity. Most intermittent fasting programs don't incorporate a recommendation for physical activity. It is easy to understand why one may feel tired and change their exercise routines.


Severe Hunger

It can also be common for those in the fasting period of an intermittent fasting eating strategy to experience severe hunger. This appetite may become more intense when they see others consuming meals.


Medications

Many people who need to take their prescription medicines with meals have a dilemma of what might happen if they take it during the fasting period. You should talk to their healthcare provider before fasting if you are taking any medications. 


If you are following a short-term intermittent fasting plan for weight loss or for a medical benefit, it's not probable you will learn basic healthier eating and cooking skills, such as how to cook with healthful oils, the way to eat more vegetables, and how to choose whole grains over refined grains.


May Promote Overeating


Throughout the non-fasting period, meal size and meal frequency aren't restricted which may promote overeating in certain people. By way of instance, if you are feeling deprived after a day of complete fasting, you might feel inclined to overeat (or eat the wrong foods) on days when feasting is permitted.


The practice of intermittent fasting is not new. A lot of the research exploring the advantages of this eating style is also relatively recent. For that reason, it's hard to tell if the benefits are long-lasting. Furthermore, researchers frequently comment that long-term studies are required to determine whether the eating program is even safe for over several months.


This sort of dietary plan would be hard for a person who eats every couple of hours with snacks between meals. It might also not be suitable for those who have conditions that need food at regular intervals because of metabolic changes brought on by their medications, such as with diabetes. Prolonged periods of food deprivation or semi-starvation puts one at risk for overeating when food is reintroduced, and might foster unhealthy behaviors like an increased fixation on food. [15,16]


People with the following conditions should abstain from intermittent fasting:
Diabetes
Eating disorders that involve unhealthy self-restriction (anorexia or bulimia nervosa)
Use of medications that need food intake
Active development stage, like in teens
Pregnancy, breastfeeding

Summary

Intermittent fasting diet plan helps in enhancing the overall health of the body with remarkable effects on cardiac health, brain health along with weight management. In today's world, where obesity is one of the most prevalent conditions and a significant cause for a number of allied ailments, an intermittent fasting diet plan can be helpful in reducing such risks. Also, comparative results for intermittent fasting diet and diet restriction reveal almost equivalent results. However, the adaptability of subjects to intermittent fasting is comparatively higher as compared to the former plans.

Also, the effects of intermittent fasting or any other diet plan must be monitored carefully and confirmed with a healthcare professional as well.

References

1. Duncan, G. G., Jenson, W. K., Fraser, R. I., & Cristofori, F. C. (1962). Correction and control of intractable obesity: practicable application of intermittent periods of total fasting. Jama, 181(4), 309-312.

2. Antoni, R., Johnston, K. L., Collins, A. L., & Robertson, M. D. (2017). Effects of intermittent fasting on glucose and lipid metabolism. Proceedings of the Nutrition Society, 76(3), 361-368.

3. Anson, R. M., Guo, Z., De Cabo, R., Iyun, T., Rios, M., Hagepanos, A.,  & Mattson, M. P. (2003). Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proceedings of the National Academy of Sciences, 100(10), 6216-6220. 

4. Anton, S., & Leeuwenburgh, C. (2013). Fasting or caloric restriction for healthy aging.

5. Patterson, R. E., Laughlin, G. A., LaCroix, A. Z., Hartman, S. J., Natarajan, L., Senger, C. M., ... & Gallo, L. C. (2015). Intermittent fasting and human metabolic health. Journal of the Academy of Nutrition and Dietetics, 115(8), 1203-1212.

6. Seimon, R. V., Roekenes, J. A., Zibellini, J., Zhu, B., Gibson, A. A., Hills, A. P., ... & Sainsbury, A. (2015). Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Molecular and cellular endocrinology, 418, 153-172.

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

8. Vasconcelos, A. R., Kinoshita, P. F., Yshii, L. M., Orellana, A. M. M., Böhmer, A. E., de Sá Lima, L., ... & Kawamoto, E. M. (2015). Effects of intermittent fasting on age-related changes on Na, K-ATPase activity and oxidative status induced by lipopolysaccharide in rat hippocampus. Neurobiology of aging, 36(5), 1914-1923.

9. Varady, K. A., & Hellerstein, M. K. (2007). Alternate-day fasting and chronic disease prevention: a review of human and animal trials. The American journal of clinical nutrition, 86(1), 7-13.

10. Jamshed, H., Beyl, R. A., Della Manna, D. L., Yang, E. S., Ravussin, E., & Peterson, C. M. (2019). Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Nutrients, 11(6), 1234.

11. Alhamdan BA, Garcia-Alvarez A, Alzahrnai AH, et al. Alternate-day versus daily energy restriction diets: which is more effective for weight loss? A systematic review and meta-analysis. Obes Sci Pract. 2016;2(3):293–302. doi:10.1002/osp4.52

12. Templeman I, Thompson D, Gonzalez J, et al. Intermittent fasting, energy balance and associated health outcomes in adults: study protocol for a randomised controlled trial. Trials. 2018;19(1):86. doi:10.1186/s13063-018-2451-8

13. NHS. Why must some medicines be taken with or after food? May 3, 2018.

14. Anton SD, Moehl K, Donahoo WT, et al. Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity (Silver Spring). 2018;26(2):254–268. doi:10.1002/oby.22065

15. Johnstone AM. Fasting–the ultimate diet?. Obesity Reviews. 2007 May 1;8(3):211-22.

16. Harvie M, Howell A. Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence. Behavioral Sciences. 2017 Jan 19;7(1):4.




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