The Power of Sleep in Recovery and Exercise Performance

Jesse Oswald • December 2, 2024

Key Points

  • Healthy adults typically require a minimum of 7 hours of sleep per night, while sleep requirements are increased during infancy, childhood, and adolescence.
  • Inconsistent sleep patterns are responsible for disrupting the circadian rhythm, promoting a vicious cycle of compromised sleep quality.
  • Sleep consists of four vital stages: N1, N2, and N3, which constitute NREM (Non-Rapid Eye Movement) sleep, and a fourth stage of rapid eye movement (REM) sleep.
  • During deep sleep, physiological processes such as the release of growth hormones occur, facilitating tissue recovery, muscle growth, and improving exercise performance


It would not be surprising to acknowledge that getting enough sleep is challenging for many people. The fast-paced modern way of living has led to the sacrifice of ensuring the appropriate amount of sleep in order to cope with daily responsibilities, making sleep deprivation a global public health matter. Poor sleep, referring to both quantity and quality, is associated with numerous detrimental health outcomes, compromising cognitive, heart, and metabolic well-being.


Yet, what defines poor sleeping status, and what is the ideal sleep regimen we should opt for? In the following article, there are going to be discussed the latest guidelines of sleep duration for all life stages, the different sleep stages and their importance regarding sleep quality, as well as the impact of sleep deprivation on recovery and exercise performance for all exercise modalities, including endurance, resistance, and HIIT training.


Sleep duration guidelines and other factors of sleep quality


Sleep duration recommendations vary across the lifespan. For healthy adults, the guidelines suggest 7 hours or more. Sleeping more than 9 hours appears to have substantial benefits only in younger adults or adults experiencing consistent sleep loss or illness. It is important to note that these recommendations do not apply to childhood, as children typically have higher sleep requirements to support growth and development. According to the National Sleep Foundation's latest guidelines, 14 to 17 hours is the goal set for newborns (0-3 months), 12 to 15 hours for infants, 9 to 12 hours for toddlers and preschoolers, and 8 to 10 hours for school-age children and adolescents.


Alongside sufficient sleep duration, a healthy sleep state is also defined by high sleep quality, meaning the effective utilization of the time spent in bed for sleeping. Many exogenous factors can affect sleep quality, such as stress, anxiety, caffeine and alcohol intake, and inconsistent sleep schedules, leading to difficulties in sleep, insomnia, and frequent awakenings during the nighttime.


Additionally, quality sleep suggests not only a regular sleep schedule but one that is also aligned with our internal clock-like regulation known as the circadian rhythm. The circadian rhythm regulates many aspects of the sleeping process and can be disrupted by many factors, including increased artificial light exposure and inconsistent sleep patterns. Hence, aligning our sleep schedule with our circadian rhythm is a principal way to ensure good quality sleep, as it ensures the optimal distribution of deep sleep and rapid eye movement (REM) sleep. The sleeping process consists of four stages: N1, N2, and N3, which constitute NREM (Non-Rapid Eye Movement) sleep, and a fourth stage of rapid eye movement (REM) sleep. NREM sleep reaches the deepest sleep state at stage N3, the most important stage of NREM sleep, determining sleep quality.

However, experiencing REM sleep is also a significant indicator of high-quality sleep. REM is a critical phase of the sleep cycle that individuals experience in the latter stages of their sleep, preparing the brain to return to consciousness. During REM sleep, brain activity resembles that of wakefulness, making it a vital sleep phase for the brain to process feelings, sort out information, dream, and undergo restorative processes. 


Therefore, engaging in a healthy sleep regimen involves adherence to the recommended sleep duration guidelines according to age group as well as pursuing sleep quality in terms of optimal sleep timing and sleep stages duration.


Sleep impact on recovery


A robust body of evidence describes the restorative effect sleep exerts on the body's molecular and cellular processes, underlying the necessity of ensuring sufficient amounts of quality sleep. Sleep’s beneficial properties in cognitive function, immunity, and recovery from illness or injury have been attributed to the secretion of several growth hormones during different phases of the sleep period.


As mentioned before, sleep involves four main stages. While all sleep stages are necessary components of the sleep cycle, the N3 stage plays a crucial role in recovery. Growth hormones, such as growth hormone and prolactin, which are vital for recovery, are highly released during this phase of deep sleep. Their secretion fosters injury healing by promoting tissue repair, regeneration, and muscle growth. Additionally, they exert beneficial properties by suppressing inflammation and promoting immunity strengthening. This enhances the body’s ability to address illnesses and infections efficiently.


In addition, growth hormone release is associated with a significant decline in cortisol levels, the stress hormone. Cortisol typically exerts catabolic effects, and prolonged elevated cortisol levels are associated with increased tissue breakdown and immunity system suppression, thus delaying the process of healing and tissue repair. Cortisol levels, in alignment with the circadian rhythm, tend to peak during the day when the individual is awake and decrease at night as the body prepares for sleep. This decline in cortisol during nighttime allows growth hormones to facilitate tissue repair and healing effectively.


It is also worth noting the action of another type of substances, cytokines. Cytokines are proinflammatory molecules released when an individual experiences a lack of sleep. Cytokines, like IL-6 and CRP, negatively affect the immunity system, impede muscle recovery, promote pain, and disrupt the autonomic nervous system balance that regulates our automatic bodily functions, such as heart rate, respiratory rate, and digestion. Therefore, their release in case of sleep deprivation can hinder efficient recovery and also exert detrimental effects on numerous vital organs. 


As a result, it’s clear that coordinated hormonal activity during sleep plays a crucial role in recovery.

Therefore, prioritizing sleep quantity and quality that guarantees the experience of all necessary sleep stages is paramount for optimal recovery.


Sleep impact on exercise performance


Numerous studies have documented the critical role of sleep in optimizing exercise performance. Their findings underline that sleep, alongside training and nutrition, hold equivalent importance as fundamental factors for peak performance.


For professional athletes, sleep requirements increase to 9 to 10 hours/day due to the increased physical and mental demands of their training sessions. While extended sleep duration is needed to ensure proper physical and cognitive recovery, most athletes find it difficult to attain sufficient sleep. This challenge stems from busy schedules, irregular sleep patterns, time-zone changes during competition periods, and the anxiety and stress they face, leading to severe sleep restriction or deprivation.


According to published data, sleep restriction or deprivation that both athletes and exercising individuals often experience seriously impacts athletic performance. This is associated with diminished ability to reach peak performance, injury susceptibility, and delayed recovery, emphasizing the significance of preserving optimal sleep patterns.


Endurance exercise 


Low-to-moderate intensity endurance exercise that reaches 50-75% of an individual’s VO2max, such as running, rowing, cycling, etc., demands high cardiorespiratory activity and sustained effort for extended training periods. Sleep, alongside other critical factors, plays a fundamental role in achieving peak performance in this type of exercise as it contributes to efficient energy replenishment. Sleep, mainly NREM sleep, achieves that by facilitating glycogen synthesis and storage in muscles and the liver, which is a primary energy resource during endurance exercise. 

Moreover, growth hormone that is extensively secreted during this sleep phase promotes muscle recovery and the storage of glucose as glycogen, contributing to efficient energy replenishment. Therefore, sleep restriction or deprivation contributes to decreased energy fuels and impaired muscle repair, ultimately diminishing the ability to maintain sustained effort during endurance activities.


Sleep deprivation has also significant impacts on cognitive function and mood. Many studies have demonstrated decreased strength, stamina, and motivation after overnight sleep loss or reduced sleep duration, leading to decreased athletic performance. Sleep deprivation also appears to increase the perception of the endurance athletes' effort, contributing to greater fatigue and exhaustion. This can elevate the risk of injuries as athletes push themselves trying to overcome the perceived strains. Lastly, feelings of frustration, anger, and confusion can also result from insufficient sleep, especially REM sleep, which is vital for cognitive restoration.


Resistance training


Resistance training imposes significant strain on the muscles, making sufficient sleep a priority to attain peak performance. As mentioned before, hormones are released during the nighttime, inducing muscle repair and growth, an essential metabolic procedure for gaining strength. While research data on the impact of sleep deprivation on resistance training performance is inconclusive, insufficient muscle repair and recovery seems to be the most likely underlying factor contributing to potential declines in performance.


In terms of cognitive function, sleep deprivation can alter the athletes’ psychomotor skills and affect their coordination, reaction time, and ability to make decisions, all parameters necessary for peak performance during resistance training. 


High-Intensity Interval Training (HIIT)


Sleep is crucial in high-intensity interval training performance as well. Specifically, getting the adequate amount of sleep enhances the body’s ability to meet the increased HIIT demands by improving stamina and promoting muscle recovery through nighttime glycogen synthesis and hormonal regulation. 


Similar to resistance training, HIIT requires proper cognitive function. Mental focus, coordination, and rapid reaction times are some of the parameters of cognitive function required during HIIT training, which appear to be threatened by sleep deprivation. 


To sum up, sleep is frequently overlooked yet fundamentally crucial for overall health, with both quantity and quality holding great significance. Quality sleep assists in preserving good health by ensuring the accomplishment of the necessary sleeping stages and the optimal secretion of hormones responsible for growth and repair. Moreover, besides recovery and tissue repair, adequate sleep is crucial for performance optimization by enhancing physiological and cognitive performance abilities.


REFERENCES


Barbato G. REM Sleep: An Unknown Indicator of Sleep Quality. Int J Environ Res Public Health. 2021 Dec 9;18(24):12976. DOI: https://doi.org/10.3390/ijerph182412976


Charest J, Grandner MA. Sleep and Athletic Performance: Impacts on Physical Performance, Mental Performance, Injury Risk and Recovery, and Mental Health. Sleep Med Clin. 2020 Mar;15(1):41-57. DOI: https://doi.org/10.1016/j.jsmc.2019.11.005 


Doherty R, Madigan SM, Nevill A, Warrington G, Ellis JG. The Sleep and Recovery Practices of Athletes. Nutrients. 2021 Apr 17;13(4):1330. DOI: 10.3390/nu13041330


Fullagar HH, Skorski S, Duffield R, Hammes D, Coutts AJ, Meyer T. Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports Med. 2015 Feb;45(2):161-86. DOI: https://doi.org/10.1007/s40279-014-0260-0 


Hirshkowitz M, Whiton K, Albert SM, Alessi C, Bruni O, DonCarlos L, Hazen N, Herman J, Adams Hillard PJ, Katz ES, Kheirandish-Gozal L, Neubauer DN, O'Donnell AE, Ohayon M, Peever J, Rawding R, Sachdeva RC, Setters B, Vitiello MV, Ware JC. National Sleep Foundation's updated sleep duration recommendations: final report. Sleep Health. 2015 Dec;1(4):233-243. DOI: https://doi.org/10.1016/j.sleh.2015.10.004


Vitale KC, Owens R, Hopkins SR, Malhotra A. Sleep Hygiene for Optimizing Recovery in Athletes: Review and Recommendations. Int J Sports Med. 2019 Aug;40(8):535-543. DOI: 10.1055/a-0905-3103


Watson AM. Sleep and Athletic Performance. Curr Sports Med Rep. 2017 Nov/Dec;16(6):413-418. DOI: 10.1249/JSR.0000000000000418


Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, Dinges DF, Gangwisch J, Grandner MA, Kushida C, Malhotra RK, Martin JL, Patel SR, Quan SF, Tasali E. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015 Jun 1;38(6):843-4. DOI: 10.5665/sleep.4716 

An Ounce of Prevention - Hyperion Health Blog

A woman is helping an older woman do exercises on an exercise ball in a gym.

What is a Kinesiologist?

By Jesse Oswald • January 29, 2025
What is a Kinesiologist?
A woman is wearing an oxygen mask while running on a treadmill.

Predicting Medical Costs with VO2max

By Jesse Oswald • January 20, 2025
Highlights Healthcare expenses are skyrocketing, with consumers and employers facing the significant brunt. Identifying those likely to get sick is critical as our resource-strapped healthcare system should focus on those likely to become the most significant burden to the system. VO2 max is a crucial longevity indicator that can also accurately predict healthcare expenses. The rampant chronic disease epidemic and the resulting surge in medical expenses is one of the most dire problems of modern societies, probably only second to climate change. Healthcare inflation is on a meteoric rise, and for those with limited or no healthcare coverage, a medical emergency is the equivalent of personal bankruptcy. A dire problem for employers In the US, employers and consumers who face rising health insurance premiums and astronomical out-of-pocket medical expenses feel the brunt of rising healthcare costs. Such is the problem that even large, well-capitalized corporations choose to send employees overseas for specific medical procedures since the cost of traveling and treatment in a foreign country is lower than the cost of care in the US. Another startling example is the infamous "northern caravan," a term that describes people with diabetes in the northern states who travel to Canada to secure their insulin supply. According to McKinsey , a survey conducted among over 300 employers highlighted that the average increase in the cost of health benefits over the past three years has been within the range of 6 to 7 percent. This survey also indicated that any rate increases exceeding 4 to 5 percent were deemed unsustainable. Interestingly, 95 percent of the surveyed employers expressed willingness to contemplate reducing benefits if costs surged by 4 percent or more. The primary cost-control measures that these employers indicated they might explore included elevating the portion of premium costs covered by employees and a potential transition to high-deductible health plans. Why is Breath Analysis relevant? Vis-a-vis this problem, the early and accurate estimation of who will get sick and how much they will cost is as critical as the treatment itself. The reason is that no other method of accurately identifying at-risk populations exists; it helps focus our scarce prevention resources and attention on those most in need. Breath analysis, AKA VO2max or metabolic testing, is an assessment that reveals two key biomarkers that provide significant predictive value for one's likelihood of developing costly chronic conditions. These two biomarkers are VO2max and the Respiratory Exchange Ratio. In this article, we will dive into VO2max to understand why it's a critical reflection of our overall health and, consequently, a window into our future healthcare spend. What is VO2max? Let's start with the basics. What is VO2max? VO2 max is the maximum amount of oxygen the human body can absorb. It is measured in terms of milliliters of oxygen consumed per kilogram of body weight. The below formula below indicates how VO2max is calculated: The numerator indicates the volume of oxygen your heart, lungs, and cells can absorb, expressed in milliliters per minute. The denominator indicates the weight of the individual represented in kilograms. 
There are many different types of fats in this picture.

Dietary Fat: An Essential Dietary Component Rather than the root of all Nutritional Health Issues

By Jesse Oswald • January 13, 2025
Key points A total fat intake between 20-35% ensures sufficient intake of essential fatty acids and fat-soluble vitamins Omega-6 PUFAs are primarily found in vegetable oils, while omega-3 PUFAs are primarily found in fatty fish and fish oils Both omega-3 PUFAs and MUFAs have established benefits for cardiovascular disease TFAs are the only dietary lipids that have a strong positive relationship with cardiovascular disease Omega-3 PUFA supplementation increases the beneficial bacteria of the human microbiome Over the last three decades, there has been a great revolution against fat due to its suspected association with several nutritional health issues, especially cardiovascular disease. There was a tremendous amount of evidence that indicated dietary cholesterol and saturated fat as the main culprits of cardiovascular disease, thus morbidity and mortality. It was when all the low-fat and no-fat dairy products started to launch, promising even complete substitution of the cholesterol-lowering heart medication if these products were exclusively consumed. Let’s start from the beginning. Dietary fat intake can vary significantly and still meet energy and nutrient needs. International guidelines suggest a total fat intake between 20% and 35% of the daily caloric consumption. This range ensures sufficient intake of essential fatty acids and fat-soluble vitamins. Not only does the quantity of the ingested fat matter, but most importantly, its quality. Some dietary fats have beneficial effects, with a significant role in maintaining good health, while others may threaten it. Which are, after all, the dietary fats? Dietary fats is a rather heterogeneous group of organic compounds, including four main types of fat, which are elaborately described in the following sections of this article. Polyunsaturated fatty acids (PUFAs) Polyunsaturated fatty acids (PUFAs) have two or more carbon-carbon double bonds. Omega-6 PUFAs and omega-3 PUFAs are the main types of PUFAs and are classified according to the location of the first unsaturated bond (sixth and third carbon atom, respectively). Alpha-Linolenic acid (ALA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and eicosapentaenoic acid (EPA) are the most important omega-3 PUFAs. ALA is an essential fatty acid that can only be obtained from diet and can be converted into EPA and then to DHA, but the rate of this conversion is finite, approximately 7.0%–21% for EPA and 0.01%–1% for DHA. In the same way, the most important omega-6 PUFAs are linoleic acid (LA) and arachidonic acid (ARA). LA is an essential fatty acid that, in order to give rise to ARA, needs to be ingested through the diet as the human body cannot synthesize it. The recommended intake for total PUFA ranges between 5% and 10% of the total energy intake, while a total omega-3 PUFA intake of 0.5%–2% and a total omega-6 PUFA intake of 2.5%-5% is suggested. A dietary ratio of omega−6/omega−3 PUFA is recommended to be 1:1–2:1 to balance their competing roles and achieve health benefits. Omega-6 and omega-3 PUFAs Omega-6 PUFAs, in the form of LA, are plentiful in most crop seeds and vegetable oils, such as canola, soybean, corn, and sunflower oils. In contrast to omega-6 PUFAs, omega-3 PUFAs are obtained from a limited range of dietary sources. Flax, chia, and perilla seeds are rich in ALA, with significant amounts also detected in green leafy vegetables. The consumption of fatty fish, such as salmon, sardines, tuna, trout, and herring, provides high amounts of EPA and DHA. Besides fish and their oils, small amounts of omega-3 PUFAs are also detected in red meat like beef, lamb, and mutton. All the above dietary sources provide EPA, DPA, DHA, LA, and ARA in different amounts, and their intake is necessary for normal physiological function. PUFAs play a critical role in many chronic diseases, affecting human cells by regulating inflammation, immune response, and angiogenesis. Omega-3 PUFAs’ role against hypertriglyceridemia has been clarified, and research indicates that systematically consuming oily fish can contribute to general heart protection. Supplementation with omega-3 PUFAs could potentially lower the risk of several cardiovascular outcomes, but the evidence is stronger for individuals with established coronary heart disease. Moreover, adequate EPA and DHA levels are necessary for brain anatomy, metabolism, and function. Although the mechanisms underlying omega-3 PUFAs' cardioprotective effects are still poorly understood, several studies have been conducted in this direction. Unfortunately, that does not hold true for their omega-6 counterparts, for which controversial emerging data tend to show anti-inflammatory behavior that needs to be further studied. Monounsaturated fatty acids (MUFAs) In contrast to PUFAs, monounsaturated fatty acids (MUFAs) are easily produced by the liver in response to the ingestion of carbohydrates. The main MUFA is oleic acid, found in plant sources, such as olive oil, olives, avocado, nuts, and seeds, while minimal amounts are also present in meat, eggs, and dairy products. Specific guidelines around MUFAs’ dietary consumption do not exist. Therefore, MUFAs are recommended to cover the remaining fat intake requirements to reach the total daily fat intake goal. A growing body of research shows that dietary MUFAs reduce or prevent the risk of metabolic syndrome, cardiovascular disease (CVD), and hypertension by positively affecting insulin sensitivity, blood lipid levels, and blood pressure, respectively. Moreover, olive oil contains several bioactive substances, possessing anti-tumor, anti-inflammatory, and antioxidant qualities. According to a meta-analysis, consuming olive oil was linked to a lower risk of developing any sort of cancer, especially breast cancer and cancer of the digestive system. Another study found that an isocaloric replacement of 5% of the energy from saturated fatty acids (SFAs) with plant MUFAs led to an 11% drop in cancer mortality over a 16-year follow-up period. Therefore, including MUFAs in the everyday diet offers multifaceted benefits in chronic disease prevention and management, including cancer and general health promotion.  Saturated fatty acids (SFAs) Saturated fatty acids (SFAs) form a heterogeneous group of fatty acids that contain only carbon-to-carbon single bonds. Whole-fat dairy, (unprocessed) red meat, milk chocolate, coconut, and palm kernel oil are all SFA-rich foods. These fatty acids have distinct physical and chemical profiles and varying effects on serum lipids and lipoproteins. Stearic, palmitic, myristic, and lauric acids are the principal SFAs found in most natural human diets. Dietary practice and guidelines recommend limiting SFA intake to <10% of the total energy (E%), while the American Heart Association suggests an even lower intake of <7 E% because total saturated fat consumption and LDL-C levels are positively correlated. However, the role of SFAs in CVDs is quite complex, and the evidence is heterogeneous. In a recent study with a 10.6-year follow-up period, which included 195,658 participants, there was no proof that consuming SFAs was linked to developing CVD while replacing saturated fat with polyunsaturated fat was linked to an increased risk of CVD. Moreover, according to 6 systematic reviews and meta-analyses, cardiovascular outcomes and total mortality were not significantly impacted by substituting saturated fat with polyunsaturated fat. Even if these analyses were to be challenged, due to heterogenous evidence, the possible reduction in CVD risk associated with replacing SFAs with PUFAs in several studies may not necessarily be an outcome of SFAs’ negative effect but rather a potential positive benefit of PUFAs. Regarding SFAs' effect on different types of cancers, associations of their intake with an increased risk of prostate and breast cancer have been indicated. Conversely, a meta-analysis showed no link between SFA intake and a higher risk of colon cancer; similarly, consuming MUFAs, PUFAs, or total fat did not affect colon cancer risk. Hence, the role of SFA consumption in preventing, promoting, or having a neutral role in serious chronic diseases has not been fully elucidated yet. Trans fatty acids (TFAs) Trans fatty acids (TFAs) are created industrially by partially hydrogenating liquid plant oils or can be naturally derived from ruminant-based meat and dairy products. TFAs are highly found in commercial baked goods, biscuits, cakes, fried foods, etc. Guidelines regarding TFAs are stringent and limit TFA intake to <1% of energy or as low as possible. In 2015, the US Food and Drug Administration declared that industrial TFAs are no longer generally recognized as safe and should be eliminated from the food supply as their consumption is strongly linked to various CVD risk factors. Specifically, TFA intake raises triglycerides and increases inflammation, endothelial dysfunction, and hepatic fat synthesis, leading to a significantly increased risk of coronary heart disease (CHD). A meta-analysis suggested that increased TFA intake led to an increase in total and LDL-cholesterol and a decrease in HDL-cholesterol concentrations. Data also indicates that TFAs may influence carcinogenesis through inflammatory pathways, but the reported data are debatable. A recent study investigated the effects of all types of dietary fat intake on CVD risk. While PUFA, MUFA, and SFA intake were not linked to higher CVD risk, dietary TFA intake showed a strong association with CVD risk. Analysis indicated PUFA intake and CVD risk were inversely correlated, and the relative risk of CVD was reduced by 5% in studies with a 10-year follow-up. Dietary lipids and the human microbiome Dietary lipids also affect human microbiota composition. Studies have identified a close association between the human microbiome and metabolic diseases, including obesity and type 2 diabetes. Diets with a high omega-6 PUFA, SFA, and TFA intake increase the amount of many detrimental bacteria in the microbiome and reduce the amount of the beneficial ones, altering the microbiota composition and inducing inflammation via the secretion of pro-inflammatory cytokines. These bacteria may disrupt the gut barrier function, allowing lipopolysaccharides (LPS) translocation, which are bacterial toxins. This condition is linked to metabolic perturbations such as dyslipidemia, insulin resistance, non-alcoholic fatty liver disease (NAFLD), and CVD. On the contrary, omega-3 PUFA (EPA and DHA) supplementation increases beneficial bacteria and limits harmful ones, enhancing intestinal barrier functioning and preventing LPS translocation and its implications. Omega-3 PUFA supplementation has also been studied as a means of mental health disorders management, but the evidence is still controversial. A possible protective impact of fish consumption on depression has been suggested by various studies, as well as a possible protective effect of dietary PUFAs on moderate cognitive impairment. A recent review of meta-analyses indicated that omega-3 PUFA supplementation might have potential value in mental health disorders, but data credibility is still weak. Dietary lipids and obesity Last but not least, obesity and its management is another field that dietary lipids intake seems to impact with their mechanisms. A diet high in PUFA has been shown to lower the total mass of subcutaneous white adipose tissue (the predominant fat type in human bodies), reduce blood lipid levels, and improve insulin sensitivity. In a study comparing PUFA and MUFA isocaloric intake, PUFA was more advantageous and lowered visceral adiposity in patients with central obesity. By stimulating brown adipose tissue, which aids energy expenditure through its elevated thermogenic activity, omega-3 PUFAs seem to elicit these positive effects in fat tissue, thus being useful in preventing and/or managing obesity. Another related study compared PUFA to SFA overfeeding in dietary surplus conditions that aimed to increase weight by 3%. While SFA overfeeding led to weight gain, primarily through the expansion of the visceral adipose tissue, PUFA overfeeding also led to weight gain, but because of a greater expansion of lean tissue mass. To sum up, dietary fats are an essential part of the human diet with many important physiologic functions, including cell function, hormone production, energy, and nutrient absorption. Moreover, dietary fat consumption is associated with positive outcomes in regard to cardiovascular disease, metabolic syndrome, cancer, and depression. Therefore, there is no reason to demonize this valuable dietary component, incriminating it for irrelevant adverse health outcomes, primarily weight loss failure and obesity. References 1. Astrup A, Magkos F, Bier DM, Brenna JT, de Oliveira Otto MC, Hill JO, King JC, Mente A, Ordovas JM, Volek JS, Yusuf S, Krauss RM. Saturated fats and health: A reassessment and proposal for food-based recommendations: JACC State-of-the-Art review. J Am Coll Cardiol. 2020;76(7):844-857. DOI: 10.1016/j.jacc.2020.05.077 2. Bojková B, Winklewski PJ, Wszedybyl-Winlewska M. Dietary fat and cancer-Which is good, which is bad, and the body of evidence. Int J Mol Sci. 2020;21(11):4114. DOI: 10.3390/ijms21114114 3. Custers, Emma EM, Kiliaan, Amanda J. Dietary lipids from body to brain. Prog Lipid Res. 2022;85:101144. DOI: 10.1016/j.plipres.2021.101144 4. de Souza RJ, Mente A, Maroleanu A, Cozma AI, Ha V, Kishibe T, Uleryk E, Budylowski P, Schünemann H, Beyene J, Anand SS. Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ. 2015;351:h3978. DOI: 10.1136/bmj.h3978 5. Gao X, Su X, Han X, Wen X, Cheng C, Zhang S, Li W, Cai J, Zheng L, Ma J, Liao M, Ni W, Liu T, Liu D, Ma W, Han S, Zhu S, Ye Y, Zeng F-F. Unsaturated fatty acids in mental disorders: An umbrella review of meta-analyses. Adv Nutr. 2022;13(6):2217-2236. DOI: 10.1093/advances/nmac084 6. Liu AG, Ford NA, Hu FB, Zelman KM, Mozaffarian D, Kris-Etherton PM. A healthy approach to dietary fats: understanding the science and taking action to reduce consumer confusion. Nutr J. 2017;16(1):53. DOI: 10.1186/s12937-017-0271-4 7. Poli A, Agostoni C, Visioli F. Dietary fatty acids and inflammation: Focus on the n-6 series. Int J Mol Sci. 2023;24(5):4567. DOI: 10.3390/ijms24054567 8. Saini RK, Keum Y-S. Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance-A review. Life Sci. 2018;203:255-267. DOI: 10.1016/j.lfs.2018.04.049 9. Saini RK, Prasad P, Sreedhar RV, Naidu KA, Shang X, Keum Y-S. Omega-3 polyunsaturated fatty acids (PUFAS): Emerging plant and microbial sources, oxidative stability, bioavailability, and health benefits-A review. Antioxidants (Basel). 2021;10(10):1627. DOI: 10.3390/antiox10101627 10. Zhao M, Chiriboga D, Olendzki B, Xie B, Li Y, McGonigal LJ, Maldonado-Contreras A, Ma Y. Substantial increase in compliance with saturated fatty acid intake recommendations after one year following the American Heart Association diet. Nutrients. 2018;10(10):1486. DOI: 10.3390/nu10101486 11. Zhu Y, Bo Y, Liu Y. Dietary total fat, fatty acids intake, and risk of cardiovascular disease: a dose-response meta-analysis of cohort studies. Lipids Health Dis. 2019;18:91. DOI: 10.1186/s12944-019-1035-2
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