The section explores the multifaceted role of fat (triacylglycerol) in human physiology, focusing on its significance as a default fuel source and its various classifications based on fatty acid makeup and glycerol backbone placement. Fat is not only a potent energy reservoir, with a lean athlete carrying a substantial amount of stored triacylglycerol, but it also exhibits pharmaceutical-like effects, influencing biological systems and cellular processes. The complex nature of fats introduces variations that can lead to anti-inflammatory, antidepressive, anticatabolic, and other effects relevant to athletes.
The digestion and absorption of fat are essential for harnessing it as a fuel source or a “nutraceutical.” The process involves enzymes such as lingual lipase in the mouth, gastric and pancreatic lipases, bile, and the formation of chylomicrons in the small intestine. The absorbed fat is then transported through the blood, and its contents are extracted by lipoprotein lipase in tissues, allowing fatty acids to enter fat or muscle cells for energy utilization.
The section introduces the concept of fatty acids, major components of fats used for energy and tissue development, and glycerol, the central structural component of triglycerides. It establishes the connection between dietary fats and their incorporation into cell membranes, influencing biochemical processes and cellular properties, leading to various beneficial effects for hard-training athletes.
Distinguishing between saturated and unsaturated fats, the text emphasizes the importance of understanding deeper classifications based on degrees of saturation, carbon-carbon double-bond positions, chain length, and fatty acid placement. These distinctions become crucial for athletes to optimize health and performance. The degree of saturation, determined by the number of carbon-carbon double bonds, categorizes fatty acids as saturated, monounsaturated, or polyunsaturated, each with distinct implications for physiological effects.
The discussion delves into the differences among saturated fatty acids, challenging the traditional view that all saturated fats negatively affect LDL cholesterol receptors. Research suggests variations even within saturated fatty acids, with stearic acid showing different atherogenic properties. Monounsaturated fatty acids, exemplified by oleic acid found in olive oil, have been associated with enhanced longevity and reduced morbidity.
Polyunsaturated fats, encompassing linoleic acid, linolenic acid, and highly unsaturated fatty acids like EPA and DHA, are explored for their opposing effects and the importance of balance in their consumption. The text underscores the role of these fatty acids in influencing inflammatory states, with EPA and DHA exhibiting anti-inflammatory properties, potentially mitigating the effects of inflammation induced by high-intensity exercise.
The intricate interplay between the chemical differences in fat types and their physiological effects is highlighted, providing athletes with valuable insights into choosing the right types of fats to optimize both health and performance. The text concludes by acknowledging the limited information on the impact of linoleic acid-based inflammation on athletic conditions such as bursitis and tendinitis. Overall, this section offers a comprehensive overview of the diverse roles and classifications of fats, providing athletes with a foundation to make informed dietary choices for optimal outcomes.
The section delves into the nuances of polyunsaturated fatty acids (PUFA), emphasizing the significance of understanding the position of carbon-carbon double bonds. The terms “omega-3” and “omega-6” gain relevance, indicating the position of the first double bond, and are crucial in differentiating anti-inflammatory effects found in fish oils (omega-3) from proinflammatory effects in most vegetable oils (omega-6). The discussion explores the rarity of carbon-carbon double bonds on PUFA molecules, offering insights into their counting from both ends of the chain, exemplified by linolenic acid, an omega-3, delta 9,12 polyunsaturated fatty acid.
The section introduces conjugated linoleic acid (CLA), a supplemental fat found in beef and dairy, with double bonds positioned closer together, exemplified by omega-7, delta 9,11 fatty acid. The narrative directs readers to the section “Fat Supplements for Athletes” for a more detailed discussion of CLA. Additionally, it highlights another positional difference related to carbon-carbon double bonds: the cis versus trans descriptor. The configuration of these double bonds, whether cis or trans, significantly impacts the physiological effects of the fatty acids.
The discussion proceeds to provide insights into the implications of cis and trans configurations on fatty acid structure, emphasizing that naturally occurring fatty acids mostly exhibit the cis configuration. It details the process of hydrogenation, where food producers create trans fats with a straight shape, akin to saturated fats. The detrimental effects of man-made trans fats, found in various processed food products, are likened to those attributed to saturated fats, both metabolically and physically. The text elucidates the concept of packing of fatty acids into cell membranes based on their shape, emphasizing the impact on metabolic and physical outcomes.
Terms such as “trans fat” and “hydrogenation” are defined, offering clarity on their relevance in processed foods and their effects on shelf life, spreadability, and mouthfeel characteristics. The discussion provides a holistic understanding of the distinctions between cis and trans configurations, shedding light on the potential health implications associated with the consumption of trans fats.
The narrative then shifts to the importance of chain length in fatty acids, emphasizing that chain length is a critical factor beyond degree of unsaturation. Fatty acid chains range from 4 to 22 carbons, with short-chain fatty acids (less than six carbons) and medium-chain fatty acids (6-12 carbons) being rare. Examples of these rare fatty acids are explored, including those produced by gut bacteria acting on dietary fiber and those present in cow’s butter. The section highlights that long-chain fatty acids (16-22 carbons) are more common and encompass mono- and polyunsaturated fats discussed earlier.
The discussion provides clarity on the theoretical rationale behind ingesting medium-chain triglycerides (MCT) for improving aerobic endurance performance. Despite the majority of studies not supporting improvements in aerobic endurance, the section acknowledges potential benefits for athletes ingesting medium-chain fatty acids, as elaborated in the section “Medium-Chain Fatty Acids.”
The section concludes by introducing fatty acid placement as a final distinction, indicating that food chemists can manipulate the arrangement of fatty acids on the glycerol “backbone” of a triacylglycerol molecule. This manipulation results in structured triacylglycerols or diacylglycerols, paving the way for advanced fat technology for athletes, a topic further explored in the section “Dietary Fat and Performance.” Overall, the section offers a comprehensive exploration of the complexities of polyunsaturated fatty acids, providing athletes with valuable insights into the structural nuances and physiological implications of different fatty acid configurations and chain lengths.
The section explores essential fatty acids, emphasizing their critical role in preventing deficiency symptoms, which humans must consume due to the absence of enzymes delta-12 and delta-15 desaturase. Linoleic acid (omega-6) and linolenic acid (omega-3) are the two nutritionally essential fatty acids, and their consumption is vital for averting symptoms such as retarded growth, dermatitis, kidney lesions, and even death. The deficiency symptoms arise because these fatty acids are integrated into longer physiologically important fatty acids, becoming part of cell membranes and forming eicosanoids. Eicosanoids, derived from essential fatty acids, play pivotal roles in inflammation and immunity, influencing various bodily systems.
The section provides concise definitions of “linoleic acid” and “linolenic acid,” underlining the overconsumption of linoleic acid and the underconsumption of linolenic acid in most Western diets. The narrative expands on the significance of linolenic acid as an essential omega-3 fatty acid with double bonds at specific positions, emphasizing its physiological importance.
A notable addition to the essential fatty acid discussion is docosahexaenoic acid (DHA), an omega-3 fatty acid with effects on cell membranes, eicosanoid production, and gene interactions. The text presents arguments for considering DHA as a third essential fatty acid due to its substantial physiological effects, particularly in improving neurological and visual function in developing infants. The benefits of DHA extend to lessening the inflammatory component of chronic diseases, reducing cortisol response to stress, and influencing various cardiovascular factors. The section acknowledges that further research is needed to determine the optimal cardiovascular and other benefits of DHA, especially in the context of potential variations in response based on testosterone concentrations in male athletes.
The discussion introduces the concept of recommended daily intakes of individual fatty acids, with a focus on DHA. The narrative emphasizes the conversion of DHA to eicosapentaenoic acid (EPA) in the body and the inclusion of both in natural sources and dietary supplements. It also mentions the potential relevance of the combined dose of DHA and EPA for cardiovascular benefits.
The section widens its scope by highlighting the inadequacy of discussions on essential fatty acids alone to underscore the impact of dietary fat on health. It delves into the concept of a balanced diet, emphasizing that Western society, including Americans, Britons, and Australians, significantly overconsumes omega-6 fat while underconsuming omega-3 fat. This imbalance, highlighted by the competition between these fats in various physiological processes, is linked to inflammation, thrombosis, and other physiological aberrations. The text draws attention to the Mediterranean diet, rich in omega-9 fatty acids (oleic acid), considered healthy and potentially capable of altering the omega-6 to omega-3 ratio, albeit to a more neutral stance relative to inflammation.
The section concludes by acknowledging the infancy of scientific research on essential fatty acids and athletic performance. While the health benefits of essential fatty acids for athletes are evident, performance studies are limited, with the anticipation that increased attention to essential fatty acids may lead to more research in this area. The example of a study examining the effects of omega-3 supplementation on young wrestlers’ pulmonary function during intensive training is cited, highlighting a potential avenue for future research in essential fatty acids and exercise performance.
The section delves into the multifaceted nature of cholesterol, acknowledging its importance as a lipid while highlighting the controversy surrounding its dietary implications. While not classified as a dietary fat, cholesterol holds significance in discussions about cardiovascular health and dietary guidelines. The narrative draws attention to the differing interpretations of its effects between the United States and Canada, with Canadian authorities downplaying its impact on serum cholesterol concentrations and cardiovascular risk. The common U.S. recommendation to limit dietary cholesterol to less than 300 mg per day is not deemed crucial in Canada’s dietary guidelines.
The section introduces the notion that dietary cholesterol might have unrecognized roles in strength athletes, challenging negative perceptions. Early research by Riechman and colleagues (2007) is cited, suggesting correlations between dietary cholesterol intake and lean mass and strength gains in older resistance trainers (60-69 years). Although the relationship is not established as causal, the observed significant link with lean mass gain raises questions about the potential advantages of dietary cholesterol. The text highlights the need for further research, especially in younger individuals, to better understand the potential benefits and reconcile them with the controversial aspects related to vascular health.
The subsequent exploration of dietary fat and performance differentiates the effects of fat between athletes and sedentary individuals or clinical patients. The narrative points out that physical training can positively alter tissue ratios of fatty acids in the body, favorably increasing omega-3 content, a shift not observed in nonexercisers. Additionally, the pursuit of lower-fat diets by athletes contributes to beneficial changes in tissue ratios of fatty acids, particularly due to reduced competition from omega-6 fatty acids. Athletes are advised that adjusting overall dietary fat intake can improve tissue ratios of omega-6 to omega-3.
However, caution is advised against extreme diets, such as very low-fat, high-fiber diets, which may induce changes in testosterone concentrations that could be counterproductive for athletes seeking advantages in athletic recovery and muscular growth. The narrative highlights the delicate balance athletes must maintain in dietary choices, especially when considering extreme dietary recommendations or decreased calorie intake. Emphasizing that fat content in the diet can range from 20% to 40% of total calories without impacting strength performance, the text underscores the importance of a nuanced approach to dietary fat for optimal athletic outcomes.
The section explores the intricate relationship between dietary fat and athletic performance, considering both long-term and acute effects. It introduces two significant phenomena related to dietary fat as a fuel during exercise: the “metabolic crossover effect” and the “duration effect” (or “fat shift”). The metabolic crossover effect describes the shift from fat oxidation at rest and lower intensities to carbohydrate usage at higher intensities during exercise. Despite the enhanced fat oxidation capacity in well-trained athletes, there exists an inverse relationship between fat burning and exercise intensity. On the other hand, the duration effect reveals a positive correlation between exercise duration and fat utilization. Prolonged, low-intensity exercise leads to a gradual shift from carbohydrate to fat as the primary fuel source.
The section emphasizes that not all bodily fat is stored in adipose cells, highlighting the role of approximately 300 g of stored intramuscular triacylglycerol. It clarifies that the crossover and duration phenomena don’t imply that body fat reduction is exclusively achieved during fasted, low- to moderate-intensity prolonged exercise. The narrative underscores the importance of exercise intensity and duration selection, balancing aerobic conditioning needs with the prevention of overtraining.
The discussion extends to the concept of fat loading, where athletes manipulate dietary fat through both food choices and supplements to support physical training adaptations. While the increase in muscle concentrations of stored triacylglycerol and fat-burning enzyme activity seems advantageous, studies reveal increased rates of perceived exertion (RPE) and inconsistent or decreased overall performance after fat loading. Researchers are cautious, and some suggest combining fat loading regimens with pre- and mid-exercise carbohydrate consumption.
The narrative transitions to the realm of fat supplements for athletes, particularly focusing on fish oils. These supplements, rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known for their anti-inflammatory and mood-elevating effects. Fish oil supplementation is explored in the context of potential benefits for athletes, including improvements in conditions like tendinitis, bursitis, osteoarthritis, and overtraining syndrome. The section highlights the potential role of omega-3 fats in reducing body fat, especially in the context of obesity-related inflammation. However, the research on omega-3 fats and muscle recovery/soreness is described as mixed and age-dependent. Overall, the section stresses the importance of correcting deficiencies rather than hypersupplementing nutrients and acknowledges the need for more sport-specific research in this domain.
The section delves into the exploration of Conjugated Linoleic Acid (CLA), a popular fatty acid supplement among athletes. CLA is recognized as a group of positional isomers, and its efficacy in humans, particularly athletes, has been a subject of study. Despite its dramatic anticatabolic and body fat-reducing qualities in animals, human studies have shown relative inefficacy. The discussion explores potential reasons for this, including different dosing methods, study duration, and species differences between humans and animals. Human intakes of CLA from foods are provided, with limited research suggesting increases in strength or lean body mass with supplementation. However, concerns have emerged regarding insulin sensitivity and fatty liver issues, prompting caution in its application. The narrative acknowledges the rarity of human studies compared to ongoing animal research.
The focus then shifts to Medium-Chain Fatty Acids, emphasizing the importance of fatty acid length in sport nutrition. Medium-chain triglycerides (MCT) derived from coconut oil and palm kernel oil behave differently in the body due to their shorter fatty acid chains. While early research in the 1980s generated interest in testing MCT as an immediate performance fuel, subsequent studies revealed no significant benefits regarding improved performance or glycogen sparing during exercise. The narrative discusses potential future avenues of interest for MCT, particularly in weight gain and body recomposition, highlighting its potential as a calorie source less likely to be stored as body fat. Recent research suggests reduced body fat with MCT ingestion.
The section concludes by introducing the concept of Structured Triglycerides, a form of special triacylglycerol molecules formed through esterification. Research suggests body fat-reducing qualities and reduced intestinal distress with structured triglycerides containing a mix of medium-chain and long-chain fatty acids. The discussion also touches on the use of diacylglycerols, introduced in Japan in 1999 and now available in the United States, which oxidize more readily during digestion, affecting absorption and metabolism. Barriers to widespread use in sports nutrition, such as technology or cost, are acknowledged. Overall, the section provides a comprehensive overview of these fatty acid supplements, their potential benefits, and the considerations surrounding their use in the context of athletic performance.