The Safety Limits Of An Extended Fast: Lessons from a Non-Model Organism

Bertile, Fabrice; Fouillen, Laëtitia; Wasselin, Thierry; Maes, Pauline; Maho, Yvon Le; Dorsselaer, Alain Van; Raclot, Thierry

doi:10.1038/srep39008

Cited by 10 publications

(8 citation statements)

References 31 publications

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“…During P3, we could hypothesize an anticipation of food intake for replenishment of the protein compartment to be prioritized in case of refeeding. Wild animals undergoing prolonged fast to breed are indeed abandoning their duty for refeeding when reaching P3 [ 72 ]. Moreover, an anticipation has already been reported in rats submitted to prolonged fasting, with a restoration of the intestine before food is yet available [ 73 ].…”

Section: Discussionmentioning

confidence: 99%

Transcriptional Changes Involved in Atrophying Muscles during Prolonged Fasting in Rats

Ibrahim

Wasselin

Challet

et al. 2020

IJMS

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Food deprivation resulting in muscle atrophy may be detrimental to health. To better understand how muscle mass is regulated during such a nutritional challenge, the current study deciphered muscle responses during phase 2 (P2, protein sparing) and phase 3 (P3, protein mobilization) of prolonged fasting in rats. This was done using transcriptomics analysis and a series of biochemistry measurements. The main findings highlight changes for plasma catabolic and anabolic stimuli, as well as for muscle transcriptome, energy metabolism, and oxidative stress. Changes were generally consistent with the intense use of lipids as fuels during P2. They also reflected increased muscle protein degradation and repressed synthesis, in a more marked manner during P3 than P2 compared to the fed state. Nevertheless, several unexpected changes appeared to be in favor of muscle protein synthesis during fasting, notably at the level of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, transcription and translation processes, and the response to oxidative stress. Such mechanisms might promote protein sparing during P2 and prepare the restoration of the protein compartment during P3 in anticipation of food intake for optimizing the effects of an upcoming refeeding, thereby promoting body maintenance and survival. Future studies should examine relevance of such targets for improving nitrogen balance during catabolic diseases.

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Section: Discussionmentioning

confidence: 99%

Transcriptional Changes Involved in Atrophying Muscles during Prolonged Fasting in Rats

Ibrahim

Wasselin

Challet

et al. 2020

IJMS

Self Cite

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show abstract

“…Three phases have been described in the course of LF in animals, such as the Emperor penguin, that undergo yearly, during 35 years (average life span) fasting periods lasting several weeks until exhaustion of energy reserves [ 114 ]. An initial phase 1, when the metabolic switch occurs, is followed by a phase of protein sparing called phase 2, lasting several days to weeks.…”

Section: Therapeutic Fasting: Clinical Impact In Contemporary Medicinmentioning

confidence: 99%

Unravelling the health effects of fasting: a long road from obesity treatment to healthy life span increase and improved cognition

et al. 2020

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In recent years a revival of interest has emerged in the health benefits of intermittent fasting and long-term fasting, as well as of other related nutritional strategies. In addition to meal size and composition a new focus on time and frequency of meals has gained attention. The present review will investigate the effects of the main forms of fasting, activating the metabolic switch from glucose to fat and ketones (G-to-K), starting 12-16 h after cessation or strong reduction of food intake. During fasting the deactivation of mTOR regulated nutrient signalling pathways and activation of the AMP protein kinase trigger cell repair and inhibit anabolic processes. Clinical and animal studies have clearly indicated that modulating diet and meal frequency, as well as application of fasting patterns, e.g. intermittent fasting, periodic fasting, or long-term fasting are part of a new lifestyle approach leading to increased life and health span, enhanced intrinsic defences against oxidative and metabolic stresses, improved cognition, as well as a decrease in cardiovascular risk in both obese and non-obese subjects. Finally, in order to better understand the mechanisms beyond fasting-related changes, human studies as well as non-human models closer to human physiology may offer useful clues. KEY-MESSAGES 1. Biochemical changes during fasting are characterised by a glucose to ketone switch, leading to a rise of ketones, advantageously used for brain energy, with consequent improved cognition. 2. Ketones reduce appetite and help maintain effective fasting. 3. Application of fasting patterns increases healthy life span and defences against oxidative and metabolic stresses. 4. Today's strategies for the use of therapeutic fasting are based on different protocols, generally relying on intermittent fasting, of different duration and calorie intake. 5. Long-term fasting, with durations between 5 and 21 days can be successfully repeated in the course of a year.

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“…Long periods of fasting, lasting several days to several weeks, are physiologic, e.g. during seasons of low sun exposure, and are still part of the life of most animals [20, 21] as well as of humans living without food conservation technologies [22].…”

Section: Introductionmentioning

confidence: 99%

Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects

et al. 2019

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Only few studies document longer periods of fasting in large cohorts including non-obese participants. The aim of this study was to document prospectively the safety and any changes in basic health and well-being indicators during Buchinger periodic fasting within a specialised clinic. In a one-year observational study 1422 subjects participated in a fasting program consisting of fasting periods of between 4 and 21 days. Subjects were grouped in fasting period lengths of 5, 10, 15 and 20±2 days. The participants fasted according to the Buchinger guidelines with a daily caloric intake of 200–250 kcal accompanied by a moderate-intensity lifestyle program. Clinical parameters as well as adverse effects and well-being were documented daily. Blood examinations before and at the end of the fasting period complemented the pre-post analysis using mixed-effects linear models. Significant reductions in weight, abdominal circumference and blood pressure were observed in the whole group (each p<0.001). A beneficial modulating effect of fasting on blood lipids, glucoregulation and further general health-related blood parameters was shown. In all groups, fasting led to a decrease in blood glucose levels to low norm range and to an increase in ketone bodies levels (each p<0.001), documenting the metabolic switch. An increase in physical and emotional well-being (each p<0.001) and an absence of hunger feeling in 93.2% of the subjects supported the feasibility of prolonged fasting. Among the 404 subjects with pre-existing health-complaints, 341 (84.4%) reported an improvement. Adverse effects were reported in less than 1% of the participants. The results from 1422 subjects showed for the first time that Buchinger periodic fasting lasting from 4 to 21 days is safe and well tolerated. It led to enhancement of emotional and physical well-being and improvements in relevant cardiovascular and general risk factors, as well as subjective health complaints.

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The Safety Limits Of An Extended Fast: Lessons from a Non-Model Organism

Cited by 10 publications

References 31 publications

Transcriptional Changes Involved in Atrophying Muscles during Prolonged Fasting in Rats

Transcriptional Changes Involved in Atrophying Muscles during Prolonged Fasting in Rats

Unravelling the health effects of fasting: a long road from obesity treatment to healthy life span increase and improved cognition

Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects

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