As discussed previously, there have been mixed results regarding the retention of fat-free mass during intermittent fasting. Colman, R. J., Anderson, R. M., Johnson, S. C., Kastman, E. K., Kosmatka, K. J., Beasley, T. M., . Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. A wide variety of subjects and experimental designs were used in the included studies, which hinders the direct comparison of different intermittent fasting programs presented in this review. If both caffeinated and decaffeinated coffee consumption is shown to increase insulin sensitivity, then coffee in general may help speed the process of reversing tolerance to glucose, which the body undergoes during a fasting period. Importantly, fasting and adipose-VEGF induce alternative activation of adipose macrophage, which is critical for thermogenesis” (Kim et al., 2017). Similar to alternate-day fasting studies, whole-day fasting studies have produced varying results, which might be attributable to a number of factors. 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Additionally, unless multiple experiments were conducted by a single laboratory, there is considerable variation in the experimental protocols used, even within a particular category of fasting. . While it appears that there is no change in 24-hour energy expenditure during reductions in meal frequency (down to 2 meals per day),57–63 resting metabolic rate has been shown to increase during short-term starvation. Study lasted 12 wks, and body composition was measured by BIA, 56 normal-weight and overweight M (control group, 59 ± 6; intervention group, 60 ± 5), Subjects randomized into intervention (FCR) and control groups. Zauner et al.43 also conducted a study of brief fasting in healthy lean male and female subjects. Annals of Neurology, 67(1), 41–52. It is possible that adding this small meal helps promote lean-mass retention during fasting, since fat-free mass was not decreased in the majority of studies that placed a small meal on the fasting days.10,13,14 A recent review by Varady19 also noted that intermittent caloric restriction may provide superior fat-free mass retention when compared with daily caloric restriction. . Seven whole-day fasting studies are summarized in Table 3.22–28 All studies combined intermittent fasting with caloric restriction (i.e., the total weekly diet was hypocaloric), and some utilized modified fasting by allowing small amounts of food intake on fasting days. cNumerical value for standard error of the mean not provided. The Journal of Nutrition, 147(7), 1437–1445. After subjects consumed 1 meal per day, decreases were seen in their body weight (65.9 ± 3.2 kg vs 67.3 ± 3.2 kg after 3 meals/d) and fat mass (14.2 ± 1.0 kg vs 16.3 ± 1.0 kg after 3 meals/d). One other study added that, “IF-induced metabolic benefits require fasting-mediated increases of vascular endothelial growth factor (VEGF) expression in white adipose tissue (WAT). Body composition was not measured, To investigate the difference between energy restriction (25%) delivered as IER or CER on anthropomorphic and metabolic variables in overweight and obese premenopausal women, 107 overweight and obese premenopausal F (40 ± 4 for both groups), Subjects randomly assigned to IER (25% energy restriction via 2 consecutive VLCD days per week) or CER (daily 25% energy restriction) for 6 mo. Conclusions can be drawn from the data showing that IF can ameliorate cognitive dysfunction and can be beneficial towards the prevention or reversal of Alzheimer’s disease. Age and energy intake interact to modify cell stress pathways and stroke outcome. Another popular method includes a 24-hour fast at least once a week followed by regular dieting on subsequent days. Journal of Gerontology, 38(1), 36–45. doi:10.1046/j.1471–4159.2003.01586.x, Meckel, Y., Ismaeel, A., & Eliakim, A. (2007). EODF treatment results in a shift in the gut microbiota composition leading to elevation of the fermentation products acetate and lactate and to the selective upregulation of monocarboxylate transporter 1 expression in beige cells.” (Li et al., 2017). The study used rat models, and the results showed that, “IF ameliorated cognitive dysfunction, prevented brain from Aβ deposition, and restored the AQP4 polarity in a mouse model of AD” (Zhang et al., 2017). In other words, it is difficult to prescribe across large populations. Alternate-day fasting has also been shown to be effective at improving several risk factors associated with cardiovascular disease. During the fasting phase, energy consumption is limited to zero calories while the eating phase is usually standardized using ad libitum feeding — although some controlled groups indicate more improvements in biomarkers. In addition to its appetite suppressing effects, there are also a few possible benefits in consuming black coffee while fasting. Lower physical activity and altered body composition in patients with haemophilia compared with healthy controls. There was also a 28.6% withdrawal rate from the study (with the typical withdrawal rates for studies at the facility being ≈ 4%–7%),21 indicating that some individuals may not be able to adhere to this pattern of eating. doi:10.1016/j.febslet.2007.02.006, Tinsley, G. M., & Bounty, P. M. (2015). Some go as far as 20 to 24-hours, but the most common approach that creates more compliancy appears to be within the 16-hour range. Therefore, it is likely that this eating pattern will eventually become a more common protocol for weight loss and prevention of diseases when further studies establish a clearer understanding of intermittent fasting’s effects. Cell Research, 27(11), 1309–1326. If your coffee were to be purchased separately in bulk-fashion, it can range anywhere from as little as $3.00-$13.00 for a pack, which can last you anywhere from weeks to months, depending on which brand, size, and type of coffee that is purchased. Moreover, this means that reducing overall calories may not be the only causation of longevity. Subjects in VLCD-1 consumed a VLCD (400–600 kcal/d) 1 d per week for 15 wk. Studies examining short-term fasting reveal important information about metabolic changes that may occur during the brief fasts used in intermittent fasting protocols. doi:10.2217/fca-2017–0038, Wan, R., Ahmet, I., Brown, M., Cheng, A., Kamimura, N., Talan, M., & Mattson, M. P. (2010). This review examines studies conducted on intermittent fasting programs to determine if they are effective at improving body composition and clinical health markers associated with disease. Intermittent fasting (IF) has gained popularity for body-composition improvement purposes. Journal of Clinical Investigation, 125(2), 478–486. Is intermittent fasting a scientifically-based dietary method?Medicina Sportiva, XII(2), 2747–2755. Nescafe Clasico Instant Coffee 10.5-ounce jar is priced at ~$7.72 at Walmart. A rich body of research on the topic has been published since then. These conclusions were made based off of primates, and only focused on caloric restriction. Methods of intermittent fasting include alternate-day fasting (ADF), periodic fasting, and daily time-restricted feeding. James et al., claimed that, “Nine of the subjects adhered to the diet and lost an average of 8% of their initial weight during the study. doi:10.1038/cr.2017.126, Li, G., Xie, C., Lu, S., Nichols, R. G., Tian, Y., Li, L., . These metabolic changes may be the basis for the benefits seen in individuals who follow an intermittent fasting program. The time points of 12, 18, 24, and 30 hours are particularly applicable to the events that may occur during intermittent fasting protocols. The relatively small amount of available research, particularly in the case of time-restricted feeding, the lack of control of macronutrient intake, and the few comparisons of differing nutrient intakes (both during ad libitum eating and during fasting periods) are limitations of the available studies. Subjects in the IF group alternated between, To examine the ability of ADF to facilitate weight loss and beneficially modulate key indicators of coronary artery disease risk in obese individuals, All subjects alternated between fasting days (≈25% of kcal needs as determined by Mifflin equation; consumed between 12 pm and 2 pm) and, To compare the effects of ADF, CR, and endurance exercise on changes in LDL and HDL particle size in overweight and obese subjects when a similar degree of weight loss is achieved, 60 overweight and obese M and F (ages for 4 groups: ADF, 47 ± 2, CR, 47 ± 3, exercise, 46 ± 3; control, 46 ± 3), Randomized, controlled, parallel-arm trial. The common theme among intermittent fasting protocols is that individuals periodically abstain from eating for periods longer than the typical overnight fast. Another common approach may also be alternate-day fasting (ADF), where the individual undergoes either a 24-hour fast followed by a “refeed” day, or it can be accomplished by completing two consecutive days of fasting followed by five days of regular dieting; this allows for the individual to compensate for the deficit in calories throughout the week, allowing for the individual to maintain their weight, or it can create an easier method in keeping calories to a minimum depending on the individuals goals. This evidence-based guide will set you down the right path to body recomposition using intermittent fasting. Therefore, this study does not provide adequate data to draw conclusions and future studies should implement controlled trials with larger number of subjects and longer study durations in humans to bring supporting evidence to these results. . Alternate-day fasting trials of 3 to 12 weeks in duration appear to be effective at reducing body weight (≈3%–7%), body fat (≈3–5.5 kg), total cholesterol (≈10%–21%), and triglycerides (≈14%–42%) in normal-weight, overweight, and obese humans. Additionally, interactions between intermittent fasting and physical activity should be examined, as it is thought that disease risk and body composition are best modified by a combined dietary and physical activity regimen.79–82 Only one study that examined the combination of an intermittent fasting protocol and exercise program was identified through the literature search,16 and endurance exercise on stationary bikes and elliptical machines was the only form used. Recent publications have indicated several successful outcomes simply due to hormonal reestablishment. The combo and ADF groups alternated between fasting days (≈25% of kcal needs as determined by Mifflin equation; consumed between 12 pm and 2 pm) and, To examine the effects of modified ADF on body weight, total body fat mass, and CVD risk factors, For 6 wk, all subjects consumed very low-calorie diets (25%–30% of energy needs) on the 3 weekly fasting days (Saturday, Monday, and Thursday) and consumed a diet of 1700–1800 kcal/d on feeding days. Searches were performed in PubMed and the university library’s OneSearch resource using the following terms: “intermittent fasting,” “alternate-day fasting,” “meal frequency AND body composition,” “reduced meal frequency,” and “fasting calorie restriction.” Inclusion criteria were as follows: 1) clinical trials conducted in human subjects; 2) male or female subjects of any age; 3) study duration of at least 3 weeks; 4) total sample size of ≥10 subjects; 5) utilization of complete or modified fasting; 6) reporting of changes in body weight and/or body composition; and 7) publication in the English language. European Journal of Applied Physiology, 102(6), 651–657. Very little information about the optimal duration of intermittent fasting programs is available. Therefore, no objective conclusions could be made about short-term intermittent fasting and cardiovascular and metabolic risk factors, and further, more controlled research should be done. Author contributions. One study structured a trial using ten subjects with a BMI > 30 and were maintained for 8 weeks on an every other day ad libitum diet, while consuming less than 20% of their normal calorie intake on the following days. Neurobiology of Aging, 10(4), 317–322. The Journal of Nutritional Biochemistry, 21(5), 413–417. Subjects in ADF group alternated between fasting days (≈25% of kcal needs as determined by Mifflin equation; consumed between 12 pm and 2 pm) and, To compare the effects of HF and LF ADF diets on body weight, body composition, and CHD risk in obese adults, 32 obese F (ages for 2 groups: ADF-HF, 42 ± 3; ADF-LF, 43 ± 2), Subjects randomized into HF or LF groups. To reiterate, from a dietary standpoint, caloric restriction diets seem to fall short when prescribed to overweight individuals due to the lack in compliancy. Intermittent Fasting and Human Metabolic Health. Improvements on cardiovascular health was observed throughout four studies using rodents. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. Intermittent Fasting Protects against Alzheimer’s Disease Possible through Restoring Aquaporin-4 Polarity. . Future research should seek to differentiate between caloric deficits induced by intermittent fasting programs and specific health benefits of fasting. This was further accompanied by the concomitant decrease in cleavage of caspase3 and p53 expression” (Tikoo, Tripathi, Kabra, Sharma, Gaikwad, 2007). In regard to that, one study observed only rats on alternate-day fasting diets survived to 30 months of age compared to a mean lifespan of 22–24 months for rats fed ad libitum (Moroi-Fetters, Mervis, London, Ingram, 1989). For example, if an individual consumed his last meal on Monday (feeding day 1) at midnight and his first meal on Wednesday (feeding day 2) at 6 am, the duration would be 30 hours. Intermittent fasting is growing in popularity because it is effective, easy to implement, and has many evidence-based benefits from improved focus, to improved digestion and has even been shown to aid in the treatment of certain cancers. Intermittent fasting promotes adipose thermogenesis and metabolic homeostasis via VEGF-mediated alternative activation of macrophage. The long-lasting outcomes of over-consuming has ultimately led to a hormonal imbalance — specifically insulin — resulting in higher rates of obesity which can lead to other health-related issues such as cardiovascular disease and diabetes mellitus. Time-restricted feeding and risk of metabolic disease: a review of human and animal studies, Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism, Glucose tolerance and skeletal muscle gene expression in response to alternate day fasting, Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma, Effect of 8 weeks of intermittent fasting on weight loss, body composition, and insulin sensitivity in obese individuals [abstract], Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults, Improvements in coronary heart disease risk indicators by alternate-day fasting involve adipose tissue modulations, Comparison of effects of diet versus exercise weight loss regimens on LDL and HDL particle size in obese adults, Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial, Alternate day fasting (ADF) with a high-fat diet produces similar weight loss and cardio-protection as ADF with a low-fat diet, Alternate day fasting increases LDL particle size independently of dietary fat content in obese humans, Alternate day fasting and endurance exercise combine to reduce body weight and favorably alter plasma lipids in obese humans, Alternate day fasting with or without exercise: effects on endothelial function and adipokines in obese humans, The effects of modified alternate-day fasting diet on weight loss and CAD risk factors in overweight and obese women. . As a result, the studies are highly inconclusive with the effects on body weight and blood lipids with some studies showing unchanged body weight (Meckel, Ismaeel, Eliakim, 2007; Aksungar, Topkaya, Akyildiz, 2007), while others show successful weight loss (Subhan, Siddiqui, Khan, Sabir, 2006). A cup of black coffee contains, at most, about two calories on average. Nonetheless, evolution takes its course, and human genetic-makeup can vary across each individual, causing more difficulty in accomplishing this lifestyle than in others. . Intermittent Fasting Attenuates Increases in Neurogenesis after Ischemia and Reperfusion and Improves Recovery. Intermittent Fasting (IF) ... as I’m currently at my lowest body fat and best body composition ever as a result of doing my workouts fasted. Despite these challenges, the literature can still be cautiously examined to give a picture of metabolic changes that may occur during brief fasting. Abbreviations and symbols: BIA, bioelectrical impedance analysis; CER, continuous energy restriction; CHD, coronary heart disease; CON: control; CR, caloric restriction; DXA, dual-energy X-ray absorptiometry; F, females; FCR, fasting calorie restriction; HDL, high-density lipoprotein; IER, intermittent energy restriction; IFCR-F; intermittent fasting caloric restriction, food-based; IFCR-L, intermittent fasting caloric restriction, liquid-based; LDL, low-density lipoprotein; M, males; NC, no change; NR, not reported; SBT, standard behavioral therapy; VLCD, very-low calorie diet; ↓: decreased. (2018, January 18). Blumenthal JA Babyak MA Sherwood Aet al. In the meantime, there have been a few observed benefits so far. Some studies6,7,9 allowed no caloric intake on fasting days, while others8,10,11,13–18 allowed caloric intake of up to 25%–30% of weight maintenance needs. To determine the feasibility of ADF in nonobese subjects and to examine the effects of ADF on body weight, resting metabolic rate, fat oxidation, and biomarkers of longevity, 16 normal-weight and overweight M (34 ± 3) and F (30 ± 1), Subjects alternated between fasting days (no calorie intake) and, A pilot study to determine the feasibility and efficacy of intermittent CR in the treatment of patients with moderate asthma, 10 obese inactive M and F with moderate asthma (age NR), All subjects alternated between fasting days (320 kcal consumption for F and 380 kcal consumption for M via canned meal-replacement shake) and, To determine if IF results in greater weight loss and improvements in insulin sensitivity than CR, Subjects randomized into CR and IF groups. The extremely limited number of time-restricted feeding studies that were included in this review makes it difficult to draw clear conclusions about the efficacy of time-restricted feeding or to compare time-restricted feeding with alternate-day fasting or whole-day fasting. Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Serlie, M. J. Fung, J., & Moore, J. The complete guide to fasting: Heal your body through intermittent, alternate-day, and extended fasting. Alternate-day fasting has been shown to reduce body weight (3%–7%), body fat (3–5.5 kg), total cholesterol (10%–21%), and triglycerides (14%–42%) in normal-weight, overweight, and obese humans.