Health effects of intermittent fasting: A brief overview

INTRODUCTION

The erratic eating pattern in modern life – in this modern life, interestingly, a breakfast, lunch, and dinner temporal pattern was mostly lacking, in contrast to the self-reported three meals/day structure of meals from the majority of the subjects. There was significant heterogeneity in the number of incidents per day at the individual level.

Fasting is giving up food and occasionally alcohol from a purely physiological perspective, yet fasting can refer to either the metabolic state attained following full digestion and absorption of a meal or the metabolic status of an individual who has not eaten during the previous night. Intermittent fasting (IF), as we know, in this modern or new lifestyle, people’s healths are ruined due to unhealthy food, which causes obesity. Obesity is a medical condition^[1] characterized by an excessive accumulation of body fat to the extent that it may have a negative effect on health. It is typically measured using the body mass index (BMI), which takes into account a person’s weight and height. In general, a BMI of 30 or higher indicates obesity, which further leads other health issues obesity mainly increases due to easily availability of fast food, lack of physical activities, etc., so to prevent this, some people do IF. It gained significant popularity in recent years. IF defined^[2] on restrict the food or dietary intake for long period of time intended for different reasons, such as weight loss, several health conditions, and for some religious purposes, and the time intervals for restricted feeding, such as 16–24 h or full day fasting for 2–4 days in a week or IF is classified in several categories whole day fasting, alternate day fasting, time restricted fasting, eat stop eat, warrior diet, periodic fasting 5–2 diet. This procedure allow intake of very low-caloric food. IF may cause many health issues in the human body, such as age-related disorders, heart-related diseases, physical abnormalities, alter mental health, nutritional deficiencies, hormonal Imbalance, and disrupt sleep schedule. However, intermittent fasting does not only have negative consequences; it also offers several positive effects. It has been found to be highly effective in managing cancer, controlling body weight, and enhancing cellular processes such as autophagy, mitochondrial function, and DNA repair.^[3] Additionally, intermittent fasting helps reduce biochemical markers like lipoproteins, triglycerides, and cholesterol, while improving insulin sensitivity. These changes collectively decrease inflammatory mediators in the body,^[4] prevent obesity-related diseases, and help manage hyperandrogenism in females [Figure 1].

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Figure 1:

Metabolic shift during intermittent fasting.

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TYPES OF IF

• 1. Complete alternative day fasting: Alternating fasting days (without consuming high energy food and drinks) with eating days (eating and drinking ) ad libitum.

• 2. Alternate day fasting: This approach permits consuming 20–25% of your energy needs on designated fasting days. It underpins the well-known 5:2 diet, where you restrict your calorie intake significantly for 2 continuous days each week and eat normally for the remaining 5 days.

• 3. Time-restricted feeding: Consume meals within a specific energy range during a designated “eating window” that spans several hours. A typical variation is an 8-h eating period followed by a 16-h fast. Both the duration of the eating and fasting periods can be adjusted as needed.

• 4. Religious fasting: A variety of fasting practices are observed for religious or spiritual reasons [Figure 2].

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Figure 2:

Classification of intermittent fasting regimens.

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BENEFITS OF IF ON THE BRAIN

• Upgraded chief capability, memory, and certain mental measures

• Improved cognition and memory^[5] may result from IF

• Dementia and other age-related diseases^[6] may progress more slowly with IF

• Research demonstrates that IF increases levels of brain-derived neurotrophic factor^[7]

• IF has the potential to extend one’s life expectancy and health

• IF may lighten age-related infections, including neurodegeneration

• Reduced accumulation of beta-amyloid in Alzheimer’s disease

• Upgraded mental capability and vascular wellbeing with IF

• Further developed brain metabolism, stress obstruction, synaptic pliancy, and neurogenesis

• Upgraded mental capability, memory, and neuronal endurance through atomic transformations

• Cognitive decline is reduced and functional recovery from stroke is facilitated by IF

• In animals, IF reduces neurodegeneration and the pathological features of epilepsy.

BENEFITS OF IF ON HEART

• Cardiovascular risk factors are reduced,^[8] and ischemic injury is prevented by IF

• IF influences cyclic guanosine monophosphate (cGMP) flagging, lipid digestion, cell grip, and aggravation

• Heart function, vulnerability to injury, and disease risk factors are affected by IF

• Obesity, heart failure, and diabetes can all be prevented through IF

• Using ketone bodies from the liver, IF encourages an organ-specific metabolic switch.

BENEFITS OF IF IN THE LIVER

• Hepatic autophagy,^[9] which is necessary for sustaining cellular homeostasis and energy balance, is triggered by IF.

• IF has the potential to treat liver diseases and protect hepatocytes from genetic and environmental factors by influencing various pathways and molecular mechanisms.

• For the health of the liver, IF can significantly lower alanine aminotransferase^[10] levels.

• IF likewise prompts a critical diminishing in aspartate aminotransferase levels, demonstrating beneficial outcomes on liver capability.

• IF’s significant effect on serum gamma-glutamyltranspeptidase levels lends credence to its positive effects on liver health.

• Alkaline phosphatase levels did not change significantly with IF, indicating that this enzyme may not be affected by IF.

• IF 5:2 routine forestalls/ameliorates non-alcoholic steatohepatitis and fibrosis.

• On the off chance that lessens the ensuing hepatocellular carcinoma (HCC) improvement without influencing all out-calorie consumption.

• During fasting, peroxisome proliferator-activated receptor alpha (PPARα) and glucocorticoid receptor-– phosphoenolpyruvate carboxykinase 1 (GR)-PCK1 aid in the progression of unsaturated fat catabolism and gluconeogenesis in hepatocytes.

• Pemafibrate, a PPAR agonist, molecularly imitates important aspects of hepatic fasting signaling.

• IF exercise has better clinical results in patients with metabolic dysfunction-associated steatotic liver disease.

• The 5:2 eating regimen essentially worked on liver firmness.

• Time-limited eating led to critical enhancements in liver steatosis.

BENEFITS OF IF IN OTHER FACTORS

• Changes in anthropometric measurements, such as lean body mass, waist circumference,^[11] fat mass, and weight loss, were seen with alternate-day fasting

• IF is a possible dietary mediation with potential medical advantages

• IF can prompt changes in body organization, cardio metabolic status, and maturing

• IF can forestall illnesses, such as diabetes, malignant growth, coronary illness, and neuropathy

• In humans, it has been demonstrated that IF alleviates metabolic syndrome^[12], asthma, rheumatoid arthritis, and Alzheimer’s disease

• IF also helps to reduce inflammatory markers, such as interleukin (IL)-2, IL-6, and c-reactive protein

BENEFITS OF IF IN THE TREATMENT OF CANCER

• IF has appeared as an assuring strategy in the treatment of cancer due to its ability to alter the gut microbiota,^[13] alter metabolism, and improve anti-tumor immunity.

• The anti-proliferative effects of IF and natural substances, such as thymoquinone, on breast cancer cell lines and the effectiveness of conventional treatments have been demonstrated by studies.

• IF’s effect on hepatic autophagy plays a pivotal part in keeping up with cell homeostasis and guarding against liver illnesses, including HCC, recommending its true capacity in liver sickness counteraction and therapy.

CARDIOMETABOLIC EFFECTS OF IF

• By lowering oxidative stress, insulin resistance,^[14] and blood pressure, these regimens may improve cardio-metabolic health

• There is also a reduction in low-density lipoprotein cholesterol and triglyceride levels; however, results vary. There is no evidence to support the other health benefits, which include better regulation of appetite and beneficial changes in the richness of the gut microbiota. In general, IF is harmless and does not lead to an increase in disordered eating patterns or disruptions in energy levels.

NEGATIVE IMPACTS OF IF

Despite its many benefits, IF carries potential risks. These include nutrient deficiencies, disrupted sleep, bone density loss, decreased testosterone in men, reduced androgen levels in premenopausal women, and increased fracture risk due to reduced bone mineral density. Psychomotor performance and mental alertness may also be impaired in certain fasting contexts, such as Ramadan.^[15] Adolescents, elderly individuals, and pregnant or lactating women are particularly vulnerable and should avoid IF unless closely supervised by healthcare professionals.^[16,17]

• Reduced accumulation of beta-amyloid in Alzheimer’s disease

• Upgraded mental capability and vascular well-being with IF

• Further developed brain metabolism, stress obstruction, synaptic pliancy, and neurogenesis

• Upgraded mental capability, memory, and neuronal endurance through atomic transformations

• Cognitive decline is reduced and functional recovery from stroke is facilitated by IF

• In animals, IF reduces neurodegeneration and the pathological features of epilepsy.

POPULATION SUITABILITY FOR IF

IF is most suitable for adults, particularly those with obesity, overweight, and metabolic syndrome, as studies show improved weight loss and cardiometabolic outcomes in these groups.^[18] However, IF is not recommended for vulnerable populations, such as pregnant or lactating women, adolescents, elderly individuals, and those with a history of eating disorders, due to potential risks, such as nutrient deficiencies, hormonal imbalance, and impaired growth.^[19]

RECOMMENDED TIME FRAME FOR IF PRACTICE

Clinical trials suggest that short-term IF interventions (8–12 weeks) are effective for weight reduction and metabolic improvements.^[20] Medium-term adherence (3–6 months) shows benefits in insulin sensitivity, lipid profile, and blood pressure. Evidence for long-term safety beyond 12 months remains limited, and further studies are required. Therefore, IF should ideally be practiced under medical supervision with periodic evaluation of nutritional status and health outcomes.^[21]

CONCLUSION

Intermittent fasting is an simple yet effective method to improve metabolic fitness. It helps weight manage, enhances metabolic Health and reduces the risk of chronic diseases. however, fasting methods have to be tailored to individual needs and practiced underneath right Guidance to make sure Safety and long term benefits.