Fasting-Mimicking-Diet does not reduce skeletal muscle function in healthy young adults: a randomized control trial

PURPOSE

The aim of this study was to evaluate the short- and long-term effects of the Fasting-Mimicking-Diet (FMD) intervention on neuromuscular parameters of force production in healthy young men.

METHODS

Twenty-four physically active men completed the study. Participants were randomly assigned to Fasting-Mimicking (FMD) or Normal Diet (ND) and asked to follow three cycles of dietary intervention. Neuromuscular parameters of force production during maximal voluntary isometric contractions (MVCs) with the leg extensors muscles and anthropometrics were measured at baseline (T0), at the end of the first cycle (T1), and 7-10 days after the 3rd cycle of the nutritional intervention (T2). The study was registered on Clinicaltrials.gov (No. NCT04476615).

RESULTS

There was a significant decrease in body mass at T1 for FMD (- 2.6 kg, ∆ from baseline, on average; p < 0.05) but not in ND (- 0.1 kg;). Neuromuscular parameters of force production, muscle volume, and MVC torque did not change or differ between groups across visits. Results were similar even when parameters were normalized by muscle volume.

CONCLUSION

The consumption of FMD in a group of young healthy male subjects showed to be feasible, and it did not affect neuromuscular parameters of force production. The results suggest that FMD could be safely adopted by strength athletes without detrimental effects on force and muscle volume. Further research in clinical population at risk of muscle mass loss, such as elderly and obese subjects with sarcopenia, is warranted.

Diet composition influences the metabolic benefits of short cycles of very low caloric intake

Diet composition, calories, and fasting times contribute to the maintenance of health. However, the impact of very low-calorie intake (VLCI) achieved with either standard laboratory chow (SD) or a plant-based fasting mimicking diet (FMD) is not fully understood. Here, using middle-aged male mice we show that 5 months of short 4:10 VLCI cycles lead to decreases in both fat and lean mass, accompanied by improved physical performance and glucoregulation, and greater metabolic flexibility independent of diet composition. A long-lasting metabolomic reprograming in serum and liver is observed in mice on VLCI cycles with SD, but not FMD. Further, when challenged with an obesogenic diet, cycles of VLCI do not prevent diet-induced obesity nor do they elicit a long-lasting metabolic memory, despite achieving modest metabolic flexibility. Our results highlight the importance of diet composition in mediating the metabolic benefits of short cycles of VLCI.

Fasting-mimicking diet prevents high-fat diet effect on cardiometabolic risk and lifespan

Diet-induced obesity is a major risk factor for metabolic syndrome, diabetes and cardiovascular disease. Here, we show that a 5-d fasting-mimicking diet (FMD), administered every 4 weeks for a period of 2 years, ameliorates the detrimental changes caused by consumption of a high-fat, high-calorie diet (HFCD) in female mice. We demonstrate that monthly FMD cycles inhibit HFCD-mediated obesity by reducing the accumulation of visceral and subcutaneous fat without causing loss of lean body mass. FMD cycles increase cardiac vascularity and function and resistance to cardiotoxins, prevent HFCD-dependent hyperglycaemia, hypercholesterolaemia and hyperleptinaemia and ameliorate impaired glucose and insulin tolerance. The effect of monthly FMD cycles on gene expression associated with mitochondrial metabolism and biogenesis in adipocytes and the sustained ketogenesis in HFCD-fed mice indicate a role for fat cell reprogramming in obesity prevention. These effects of an FMD on adiposity and cardiac ageing could explain the protection from HFCD-dependent early mortality.

Intermittent and Periodic Fasting, Hormones, and Cancer Prevention

The restriction of proteins, amino acids or sugars can have profound effects on the levels of hormones and factors including growth hormone, IGF-1 and insulin. In turn, these can regulate intracellular signaling pathways as well as cellular damage and aging, but also multisystem regeneration. Both intermittent (IF) and periodic fasting (PF) have been shown to have both acute and long-term effects on these hormones. Here, we review the effects of nutrients and fasting on hormones and genes established to affect aging and cancer. We describe the link between dietary interventions and genetic pathways affecting the levels of these hormones and focus on the mechanisms responsible for the cancer preventive effects. We propose that IF and PF can reduce tumor incidence both by delaying aging and preventing DNA damage and immunosenescence and also by killing damaged, pre-cancerous and cancer cells.

Time-Restricted Eating, Intermittent Fasting, and Fasting-Mimicking Diets in Weight Loss

PURPOSE OF REVIEW

This article reviews the current literature on dietary interventions, including time-restricted eating (TRE), intermittent fasting (IF), and fasting-mimicking diets (FMD) and their effects on weight loss.

RECENT FINDINGS

Dietary interventions, primarily known for their potential health benefits, are attracting considerable interest also for their effects on weight loss. The literature suggests that many popular diets can induce weight loss but only a limited number of studies actually demonstrate long-term weight loss efficacy. Here we present an update on the latest studies on some of the most popular dietary interventions able to trigger the physiology of fasting and highlight their impact on weight loss in overweight or obese individuals.

Periodic and Intermittent Fasting in Diabetes and Cardiovascular Disease

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is one of the leading causes of death globally. Nutrition plays a central role in CVD risk by affecting aging, adiposity, glycemia, blood pressure, cholesterol, inflammation, and other risk factors and can affect CVD risk not only based on calorie intake and dietary composition but also the timing and range of meals. This review evaluates the effects of fasting, fasting-mimicking diets, and time-restricted eating on the reduction of CVD risk factors and provides initial data on their potential to serve as CVD prevention and treatment therapies.

RECENT FINDINGS

Intermittent fasting (IF), time-restricted eating (TRE), prolonged fasting (PF), and fasting-mimicking diets (FMD) show promise in the reduction of CVD risk factors. Results on IF, TRE, PF, and FMD on CVD risk factors are significant and often independent of weight loss, yet long-term studies on their effect on CVD are still lacking. Coupling periodic and prolonged, or intermittent and more frequent cycles of fasting or fasting-mimicking diets, designed to maximize compliance and minimize side effects, has the potential to play a central role in the prevention and treatment of CVD and metabolic syndrome.

Correction to: Fasting in diabetes treatment (FIT) trial: study protocol for a randomised, controlled, assessor-blinded intervention trial on the effects of intermittent use of a fasting-mimicking diet in patients with type 2 diabetes

An amendment to this paper has been published and can be accessed via the original article.

Abstract CT075: Fasting-mimicking diet and hormone therapy modulates metabolic factors to promote breast cancer regression and reduce side effects

Breast cancer (BC) is the most common malignancy with 1.7 million new diagnoses/year and is responsible for more than 450,000 yearly deaths worldwide. Two thirds of BC express the estrogen receptor (ER) and/or progesterone receptor and are referred to as hormone receptor-positive (HR+) BC. Endocrine therapy (ET) is usually active in these tumors, although drug resistance and side effects limit its benefit. Growth factor signaling through the PI3K/AKT/mammalian target of rapamycin (mTOR) and MAP kinase axes enhances ER activity and is a key mechanism underlying endocrine resistance. Water-only fasting (fasting) or plant-based, low-calorie, carbohydrate- and protein-restricted fasting-mimicking diets (FMDs) reduce circulating growth factors, such as insulin and IGF1 Therefore, we hypothesized that these dietary interventions could be used to enhance the activity of ET and delay the occurrence of resistance. For our in vitro experiments we used the HR+ BC cell lines, MCF7, T47D, and ZR-75-1, as well as metastases-derived organoids from patients with HR+ BC. Our in vivo experiments in mouse xenografts of human BC cell lines, were conducted in six-to-eight-week old female NOD SCID or athymic Nude-FoxN1 mice treated with ET w/ or w/o 48-72 hours of fasting/FMD. We monitored tumor growth and mouse survival and collected tumor masses and blood to detect circulating levels of several growth factors, adipokines and cytokines. In vivo add back experiments with fasting-reduced factors were done with IGF1, insulin and leptin. Circulating growth factors and adipo-cytokines were also detected in blood samples from 36 patients with HR+ BC, who were enrolled in either one of two clinical trials (NCT03595540 and NCT03340935) assessing safety and feasibility of periodic FMD in cancer patients. Patient nutritional status and response to treatment were also monitored in our clinical trials.We found that in HR+ BC models, periodic fasting or FMD enhanced tamoxifen and fulvestrant activity by lowering circulating IGF1, insulin, and leptin levels and by blocking AKT-mTOR signaling via EGR1 and PTEN upregulation. When fulvestrant was combined with palbociclib (a cyclin-dependent kinase 4/6 inhibitor), adding periodic FMD cycles promoted long-lasting tumour regressions and reverted acquired resistance to this regime. Moreover, both fasting and FMD prevented tamoxifen-induced endometrial hyperplasia. In HR+ BC patients receiving ET, FMD cycles caused metabolic changes analogous to those observed in mice, including reduced leptin and IGF1 levels, which were found to remain low for extended periods. In mice, these long-lasting effects were associated with carryover anticancer activity. Overall, our results provide the rationale for conducting further clinical studies of fasting-based dietary strategies as an adjuvant to ET w/ or w/o CDK4/6 inhibitors in patients with HR+ BC.

Citation Format: Irene Caffa, Vanessa Spagnolo, Pamela Becherini, Francesca Valdemarin, Claudio Vernieri, Min Wei, Sebastian Brandhorst, Chiara Zucal, Else Driehuis, Lorenzo Ferrando, Luca Mastracci, Michele Cilli, Francesco Piacente, Anna Laura Cremonini, Mario Passalacqua, Valerio Vellone, Gabriele Zoppoli, Michele Cea, Giulia Salvadori, Salvatore Cortellino, Hans Clevers, Filippo De Braud, Alessandro Provenzani, Valter D. Longo, Alessio Nencioni. Fasting-mimicking diet and hormone therapy modulates metabolic factors to promote breast cancer regression and reduce side effects [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT075.

A Distinct Brain-Gut-Microbiome Profile Exists for Females with Obesity and Food Addiction

BACKGROUND

Alterations in brain-gut-microbiome interactions have been implicated as an important factor in obesity. This study aimed to explore the relationship between food addiction (FA) and the brain-gut-microbiome axis, using a multi-omics approach involving microbiome data, metabolomics, and brain imaging.

METHODS

Brain magnetic resonance imaging was obtained in 105 females. FA was defined by using the Yale Food Addiction Scale. Fecal samples were collected for sequencing and metabolomics. Statistical analysis was done by using multivariate analyses and machine learning algorithms.

RESULTS

Of the females with obesity, 33.3% exhibited FA as compared with 5.3% and 0.0% of females with overweight and normal BMI, respectively (P = 0.0001). Based on a multilevel sparse partial least square discriminant analysis, there was a difference in the gut microbiome of females with FA versus those without. Differential abundance testing showed Bacteroides, Megamonas, Eubacterium, and Akkermansia were statistically associated with FA (q < 0.05). Metabolomics showed that indolepropionic acid was inversely correlated with FA. FA was also correlated with increased connectivity within the brain's reward network, specifically between the intraparietal sulcus, brain stem, and putamen.

CONCLUSIONS

This is the first study to examine FA along the brain-gut-microbiome axis and it supports the idea of targeting the brain-gut-microbiome axis for the treatment of FA and obesity.

A fasting-mimicking diet and vitamin C: turning anti-aging strategies against cancer

In search of anti-aging interventions with differential effects on normal and cancer cells, we show that cycles of a fasting-mimicking diet plus pharmacological doses of vitamin C can be effective in targeting KRAS-mutant cancers. This approach represents a promising strategy able to protect the organism while killing cancer cells.

Fasting-mimicking diet and hormone therapy induce breast cancer regression

Approximately 75% of all breast cancers express the oestrogen and/or progesterone receptors. Endocrine therapy is usually effective in these hormone-receptor-positive tumours, but primary and acquired resistance limits its long-term benefit^1,2. Here we show that in mouse models of hormone-receptor-positive breast cancer, periodic fasting or a fasting-mimicking diet^3-5 enhances the activity of the endocrine therapeutics tamoxifen and fulvestrant by lowering circulating IGF1, insulin and leptin and by inhibiting AKT-mTOR signalling via upregulation of EGR1 and PTEN. When fulvestrant is combined with palbociclib (a cyclin-dependent kinase 4/6 inhibitor), adding periodic cycles of a fasting-mimicking diet promotes long-lasting tumour regression and reverts acquired resistance to drug treatment. Moreover, both fasting and a fasting-mimicking diet prevent tamoxifen-induced endometrial hyperplasia. In patients with hormone-receptor-positive breast cancer receiving oestrogen therapy, cycles of a fasting-mimicking diet cause metabolic changes analogous to those observed in mice, including reduced levels of insulin, leptin and IGF1, with the last two remaining low for extended periods. In mice, these long-lasting effects are associated with long-term anti-cancer activity. These results support further clinical studies of a fasting-mimicking diet as an adjuvant to oestrogen therapy in hormone-receptor-positive breast cancer.

Fasting in diabetes treatment (FIT) trial: study protocol for a randomised, controlled, assessor-blinded intervention trial on the effects of intermittent use of a fasting-mimicking diet in patients with type 2 diabetes

BACKGROUND

Caloric restriction is an effective way to treat Type 2 diabetes (T2D). However, chronic and severe restriction of food intake is difficult to sustain and is known to promote slower metabolism. Intermittent and frequent fasting can exert similar metabolic effects, but may be even more challenging for most patients. A fasting-mimicking diet (FMD) is low in calories, sugars and proteins, but includes relatively high levels of plant based complex carbohydrates and healthy fats. The metabolic effects of such a diet mimic the benefits of water-only fasting. The effects of a FMD applied periodically in T2D patients are still unknown. The Fasting In diabetes Treatment (FIT) trial was designed to determine the effect of intermittent use (5 consecutive days a month during a year) of a FMD in T2D patients on metabolic parameters and T2D medication use compared to usual care.

METHODS

One hundred T2D patients from general practices in the Netherlands with a BMI ≥ 27 kg/m², treated with lifestyle advice only or lifestyle advice plus metformin, will be randomised to receive the FMD plus usual care or usual care only. Primary outcomes are HbA1c and T2D medication dosage. Secondary outcomes are anthropometrics, blood pressure, plasma lipid profiles, quality of life, treatment satisfaction, metabolomics, microbiome composition, MRI data including cardiac function, fat distribution and ectopic fat storage, cost-effectiveness, and feasibility in clinical practice.

DISCUSSION

This study will establish whether monthly 5-day cycles of a FMD during a year improve metabolic parameters and/or reduce the need for medication in T2D. Furthermore, additional health benefits and the feasibility in clinical practice will be measured and a cost-effectiveness evaluation will be performed.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov. Identifier: NCT03811587. Registered 21th of January, 2019; retrospectively registered.

Fasting mimicking diet as an adjunct to neoadjuvant chemotherapy for breast cancer in the multicentre randomized phase 2 DIRECT trial

Short-term fasting protects tumor-bearing mice against the toxic effects of chemotherapy while enhancing therapeutic efficacy. We randomized 131 patients with HER2-negative stage II/III breast cancer, without diabetes and a BMI over 18 kg m^-2, to receive either a fasting mimicking diet (FMD) or their regular diet for 3 days prior to and during neoadjuvant chemotherapy. Here we show that there was no difference in toxicity between both groups, despite the fact that dexamethasone was omitted in the FMD group. A radiologically complete or partial response occurs more often in patients using the FMD (OR 3.168, P = 0.039). Moreover, per-protocol analysis reveals that the Miller&Payne 4/5 pathological response, indicating 90-100% tumor-cell loss, is more likely to occur in patients using the FMD (OR 4.109, P = 0.016). Also, the FMD significantly curtails chemotherapy-induced DNA damage in T-lymphocytes. These positive findings encourage further exploration of the benefits of fasting/FMD in cancer therapy. Trial number: NCT02126449.

Fasting-Mimicking Diet Modulates Microbiota and Promotes Intestinal Regeneration to Reduce Inflammatory Bowel Disease Pathology

Dietary interventions are potentially effective therapies for inflammatory bowel diseases (IBDs). We tested the effect of 4-day fasting-mimicking diet (FMD) cycles on a chronic dextran sodium sulfate (DSS)-induced murine model resulting in symptoms and pathology associated with IBD. These FMD cycles reduced intestinal inflammation, increased stem cell number, stimulated protective gut microbiota, and reversed intestinal pathology caused by DSS, whereas water-only fasting increased regenerative and reduced inflammatory markers without reversing pathology. Transplants of Lactobacillus or fecal microbiota from DSS- and FMD-treated mice reversed DSS-induced colon shortening, reduced inflammation, and increased colonic stem cells. In a clinical trial, three FMD cycles reduced markers associated with systemic inflammation. The effect of FMD cycles on microbiota composition, immune cell profile, intestinal stem cell levels and the reversal of pathology associated with IBD in mice, and the anti-inflammatory effects demonstrated in a clinical trial show promise for FMD cycles to ameliorate IBD-associated inflammation in humans.

When Fasting Gets Tough, the Tough Immune Cells Get Going-or Die

Cycles of fasting reduce autoimmunity and activate lymphocyte-dependent killing of cancer cells, but the mechanisms remain poorly understood. Three studies in this issue of Cell begin to reveal the drastic and complex effects of fasting and severe calorie restriction on the levels and localization of different immune cells and the mechanisms responsible for them.

Dietary Restrictions and Nutrition in the Prevention and Treatment of Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death in many developed countries and remains one of the major diseases strongly affected by the diet. Nutrition can affect CVD directly by contributing to the accumulation of vascular plaques and also indirectly by regulating the rate of aging. This review summarizes research on nutrition and CVD incidence based on a multipillar system that includes basic research focused on aging, epidemiological studies, clinical studies, and studies of centenarians. The relevant research linking nutrition and CVD with focus on macronutrients and aging will be highlighted. We will review some of the most relevant studies on nutrition and CVD treatment, also focusing on interventions known to delay aging. We will discuss both everyday dietary compositions, as well as intermittent and periodic fasting interventions with the potential to prevent and treat CVD.

Protein Quantity and Source, Fasting-Mimicking Diets, and Longevity

Dietary modifications, including caloric restriction, dietary restriction, various intervals of fasting, and even limiting the time when food is consumed can have a pronounced impact on longevity. In addition, dietary modifications are powerful interventions to delay, prevent, or treat many aging-related diseases such as cancer and diabetes. Restricting amino acid and protein intake generally decreases aging-related comorbidities and thereby increases health and longevity. However, chronic dietary interventions are likely not feasible for most people due to low adherence to dietary protocols or resistance to drastic changes to lifestyle, and might even cause detrimental effects, possibly by negatively affecting the immune system and wound healing. The periodic use of low-protein, low-calorie fasting-mimicking diets (FMDs) has the potential to promote health benefits, while minimizing the burden of chronic restriction. Protein restriction and FMDs together have the potential to play an important complementary role in medicine by promoting disease prevention and treatment, and by delaying the aging process at least in part by stimulating stem cell-based regeneration in periods of normal food intake after periodic FMD cycles. The aim of this narrative review is to summarize research on the impact of protein restriction on health and longevity in model organisms and to discuss the implementation of an FMD in mice and in human clinical trials and its effects on biomarkers of healthy aging. Taking into account the importance of sex on aging and diet, we include this information in all discussed studies. Whereas for some model organisms of aging, such as rodents, many studies are available, results are more limited for primates and/or humans.

Abstract P1-15-20: DIetary REstriction as an adjunct to neoadjuvant ChemoTherapy for HER2-negative breast cancer: Final results from the DIRECT trial (BOOG 2013-04)

Background:

Short term fasting (STF) protects from toxicity, while enhancing the efficacy of chemotherapy in cancer bearing mice and is a promising strategy to enhance the efficacy and tolerability of chemotherapy in humans. A specifically designed low calorie, low amino acid substitution diet (“Fasting Mimicking Diet”, FMD) has similar effects in vivo during chemotherapy as STF. The DIRECT trial evaluates the impact of FMD on toxicity and efficacy of neoadjuvant chemotherapy in women with HER2-negative early breast cancer.

Patients and methods:

Eligible patients had histologically confirmed, HER2-negative, stage II/III early breast cancer, adequate bone marrow, liver and renal function, BMI &gt; 19kg/m2 and absence of diabetes mellitus. Women receiving 8 neo-adjuvant AC-T courses (adriamycin/cyclophosphamide - docetaxel) or 6 FEC-T courses (5-fluorouracil, epirubicin and cyclophosphamide - docetaxel); day 1, q 3 weeks, were randomized to receive FMD or regular diet for 3 days prior to and at the day of chemotherapy and 3 days prior to surgery. The FMD group received no dexamethasone during the AC or FEC courses. The primary endpoint of the phase II part was feasibility and grade III/IV toxicity and of the phase III pathological complete response (pCR) rate. Additionally, in a side study increase in DNA damage in lymphocytes before and three hours after chemotherapy was compared between the 2 arms.

Results

From February 2014 to January 2018 131 patients from 11 participating Dutch centers were randomized, whereof 100 received AC-T and 31 received FEC-T. Sixty-six of the patients received FMD. Compliance to the diet was low as 32% fasted at least half of the cycles and 24% of patients fasted during all of cycles. The main reasons of non-compliance were food aversion induced by chemotherapy and the taste of the diet. Intention to treat grade III/IV toxicity was not significantly different between the standard arm (67,2%) and in the FMD arm (79,4%), although the majority of the toxicities in the FMD arm were assessed in patients that did not complete the FMD diet preceding the measurements. The total overall pCR rate was 12,8%, lower than assumed in the sample size calculation and would therefore need minimally a doubling in patient numbers to be able to reach the expected pCR difference between both arms. Due to the poor compliance, slow accrual rate and low overall pCR rate the DIRECT study terminated after completion of the phase II part. Subgroup analysis will be presented at SABCS. In a side study, DNA damage after chemotherapy was significantly less increased in lymphocytes in the FMD group as compared to the control group (p=0.043).

Conclusion

The effect of STF on toxicity and efficacy of chemotherapy was not established due to poor compliance, however STF by FMD reduced a transient increase in chemotherapy induced DNA damage. Close monitoring of patients by nutritionists with expertise in low calorie diets as well as diets with a more variable taste are probably needed to successfully examine the impact on adverse effects and tumor biology.

Citation Format: de Groot S, Lugtenberg RT, Welters MJ, Ehsan I, Vreeswijk MP, Smit VT, de Graaf H, Heijns JB, Portielje JE, van de Wouw AJ, Imholz AL, Kessels LW, Vrijaldenhoven S, Baars A, Meershoek-Klein Kranenbarg E, Duijm-de Carpentier M, van Leeuwen-Stok E, Putter H, Longo VD, van der Hoeven JJ, Nortier JW, Pijl H, Kroep JR. DIetary REstriction as an adjunct to neoadjuvant ChemoTherapy for HER2-negative breast cancer: Final results from the DIRECT trial (BOOG 2013-04) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-20.

Programmed longevity, youthspan, and juventology

The identification of conserved genes and pathways that regulate lifespan but also healthspan has resulted in an improved understanding of the link between nutrients, signal transduction proteins, and aging but has also provided evidence for the existence of multiple “longevity programs,” which are selected based on the availability of nutrients. Periodic fasting and other dietary restrictions can promote entry into a long‐lasting longevity program characterized by cellular protection and optimal function but can also activate regenerative processes that lead to rejuvenation, which are independent of the aging rate preceding the restricted period. Thus, a “juventology”‐based strategy can complement the traditional gerontology approach by focusing not on aging but on the longevity program affecting the life history period in which mortality is very low and organisms remain youthful, healthy, and fully functional.

Fasting and cancer: molecular mechanisms and clinical application

The vulnerability of cancer cells to nutrient deprivation and their dependency on specific metabolites are emerging hallmarks of cancer. Fasting or fasting-mimicking diets (FMDs) lead to wide alterations in growth factors and in metabolite levels, generating environments that can reduce the capability of cancer cells to adapt and survive and thus improving the effects of cancer therapies. In addition, fasting or FMDs increase resistance to chemotherapy in normal but not cancer cells and promote regeneration in normal tissues, which could help prevent detrimental and potentially life-threatening side effects of treatments. While fasting is hardly tolerated by patients, both animal and clinical studies show that cycles of low-calorie FMDs are feasible and overall safe. Several clinical trials evaluating the effect of fasting or FMDs on treatment-emergent adverse events and on efficacy outcomes are ongoing. We propose that the combination of FMDs with chemotherapy, immunotherapy or other treatments represents a potentially promising strategy to increase treatment efficacy, prevent resistance acquisition and reduce side effects.

Starvation, Stress Resistance, and Cancer

Cancer cells are characterized by dysregulation in signal transduction and metabolic pathways leading to increased glucose uptake, altered mitochondrial function, and the evasion of antigrowth signals. Fasting and fasting-mimicking diets (FMDs) provide a particularly promising intervention to promote differential effects in normal and malignant cells. These effects are caused in part by the reduction in IGF-1, insulin, and glucose and the increase in IGFBP1 and ketone bodies, which generate conditions that force cancer cells to rely more on metabolites and factors that are limited in the blood, thus resulting in cell death. Here we discuss the cellular and animal experiments demonstrating the differential effects of fasting on normal and cancer cells and the mechanisms responsible for these effects.