Fasted cardio is a hot topic in the fitness world, but does it really offer an edge when it comes to fat loss? In this article, we’ll dive deep into what fasted cardio is, examine the science behind it, and explore its relevance in different training programs including contest prep, off-season, and lifestyle routines.
What is Fasted Cardio?
Fasted cardio is a workout strategy where aerobic exercises are performed on an empty stomach, usually after a period of fasting that most commonly lasts overnight. This approach is based on the principle that glycogen stores are low after an extended period without food, leading the body to utilize stored fat as the primary source of energy.
Mechanism of Action
In a fed state, your body has readily available glucose and glycogen (stored form of glucose) to fuel workouts. However, in a fasted state, these readily available energy sources are depleted. As a result, the body is thought to shift its energy source from carbohydrates to stored fat, increasing fat oxidation.
Timing and Duration
The most common time to perform fasted cardio is in the morning after waking up, following an overnight fast. The fasting period should ideally be at least 8 hours to ensure a shift towards fat metabolism. The duration of the cardio session can vary but often ranges from 20 to 60 minutes, depending on individual goals and tolerance levels.
Types of Exercises
The types of exercises performed during fasted cardio are typically low to moderate intensity to allow for sustained effort without the need for immediate energy from carbohydrates. Common exercises include walking, jogging, cycling, and elliptical workouts.
Who Uses It?
Fasted cardio is often popular among bodybuilders, fitness models, and athletes who are aiming for reduced body fat levels. However, it’s also used by regular fitness enthusiasts seeking fat loss benefits. Its popularity arises from the belief that it’s more effective for fat loss compared to cardio performed in a fed state.
By understanding the intricacies of what fasted cardio is, one can make a more informed decision about whether to incorporate it into different training programs, from contest prep to off-season and lifestyle-focused routines.
The Science Behind Fasted Cardio
Fat Oxidation vs. Overall Fat Loss
The concept that fasted cardio increases fat oxidation during exercise stems from the physiological shift toward using stored fat as fuel due to depleted glycogen levels. Research shows an increase in fat oxidation rates during fasted cardio when compared to fed-state cardio (Horowitz, Mora-Rodriguez, Byerley, & Coyle, 1997).
However, the critical point here is that fat oxidation does not necessarily equate to long-term fat loss. Fat loss is more influenced by your overall caloric balance—calories in vs. calories out—over an extended period. The acute increase in fat oxidation during a single session may not have a significant impact on overall body composition, particularly if the calorie intake later in the day compensates for the morning’s energy expenditure.
Meta-Analyses and Long-term Impact
Meta-analyses have been instrumental in providing a comprehensive view of the efficacy of fasted cardio. A meta-analysis by Schoenfeld et al. (2014) assessed the long-term effects and concluded that there were no significant differences in fat loss or body composition between fasted and non-fasted aerobic exercise. This implies that the overall energy balance is the dominating factor in determining fat loss, rather than the metabolic subtleties of fasted versus fed-state exercise.
Similarly, a study by Paoli et al. (2011) evaluated whether fasted cardio had any influence on weight loss and body composition and found negligible differences. The study concluded that when caloric intake and exercise intensity are matched, there’s little to no difference in the outcomes based on the timing of food intake relative to the workout.
The scientific evidence suggests that while fasted cardio may increase fat oxidation rates in the short term, this does not necessarily translate to greater overall fat loss over an extended period. Meta-analyses and long-term studies have generally found no significant difference between fasted and fed-state cardio for affecting body composition changes. Some athletes report higher energy levels and better performance when exercising on an empty stomach. However, this is more about personal preference and comfort rather than any metabolic advantage from being in a fasted state.
- Horowitz, J. F., Mora-Rodriguez, R., Byerley, L. O., & Coyle, E. F. (1997). Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise. American Journal of Physiology-Endocrinology and Metabolism, 273(4), E768-E775.
- Schoenfeld, B. J., Aragon, A. A., Wilborn, C. D., Krieger, J. W., & Sonmez, G. T. (2014). Body composition changes associated with fasted versus non-fasted aerobic exercise. Journal of the International Society of Sports Nutrition, 11(1), 54.
- Paoli, A., Marcolin, G., Zonin, F., Neri, M., Sivieri, A., & Pacelli, Q. F. (2011). Exercising fasting or fed to enhance fat loss? Influence of food intake on respiratory ratio and excess postexercise oxygen consumption after a bout of endurance training. International Journal of Sport Nutrition and Exercise Metabolism, 21(1), 48-54.
The debate surrounding the efficiency and sustainability of long dieting periods with smaller caloric deficits versus shorter dieting periods with larger deficits has garnered much attention in the bodybuilding and fitness communities. Central to this discussion is the phenomenon of metabolic adaptation, a complex set of physiological changes where the body reduces its metabolic rate to conserve energy. One key factor in metabolic adaptation is the role of the thyroid gland, specifically the production of thyroid hormones T3 and T4, which are crucial for regulating metabolism. This article will delve into both dieting approaches and their effects on metabolism, thyroid function and muscle mass providing insight into which may be the optimal strategy for body composition.
Shorter Dieting Periods with Larger Deficits
While shorter dieting periods with larger caloric deficits offer the appeal of quick results, the metabolic implications can be more complex. A significant caloric deficit sends a signal to the body, via the pituitary gland to the thyroid, to conserve energy, activating survival mechanisms that reduce metabolic rate, sometimes referred to as “starvation mode.” This reduction in metabolic rate can make it increasingly difficult to continue losing weight and may lead to a plateau with further reduction is calories, increasing the rate of muscle loss.
Even after the dieting period is over, the body may continue to operate at this reduced metabolic rate for longer periods of time, another drawback of Metabolic Adaptation. This adaptation can make weight maintenance and future weight loss efforts more challenging. According to a study published in the “International Journal of Obesity,” participants of “The Biggest Loser” competition experienced a significant and persistent drop in their resting metabolic rate, even six years after the end of the competition .
For those in long dieting phases like Contest Prep, it’s crucial to be aware of this metabolic slowdown. The metabolic adaptations that occur due to larger caloric deficits can make it challenging to achieve the desired physique within the competition timeline. Therefore, if opting for this approach, it’s essential to have contingency plans in place to counterbalance the potential negative metabolic effects.
Long Dieting Periods with Smaller Deficits
Opting for longer dieting periods with smaller caloric deficits offers some advantages, primarily in the form of less drastic metabolic adaptations. While still inducing a caloric deficit sufficient for weight loss, smaller deficits are less likely to trigger the severe hormonal responses that larger deficits can. This makes it easier to maintain a more stable metabolic rate over the long term.
A 2009 study found that moderate caloric restriction did not produce the same extent of metabolic slowdown as experienced in more extreme caloric restriction . Additionally, smaller deficits over an extended period offer the advantage of muscle preservation. According to a review in the International Journal of Sport Nutrition and Exercise Metabolism, adequate protein intake alongside a moderate caloric deficit can optimize muscle protein synthesis, aiding in the retention of lean muscle mass during weight loss .
For those in the Off-season or focusing on Lifestyle changes, this approach provides a more sustainable pathway for long-term metabolic health and easier dieting phase, to include preps. It allows for greater flexibility in dietary choices, making it easier to adhere to in the long run. However, it’s important to note that the slower rate of weight loss might not be suitable for those on a tight Contest Prep schedule.
In the realm of long dieting periods with smaller caloric deficits, it’s crucial to discuss not just metabolic implications but also psychological factors. Research indicates that more extended, moderate dieting phases can be psychologically easier to adhere to, increasing long-term success . Moreover, the flexibility in caloric intake means athletes are less likely to feel deprived or restricted, making it more likely for them to maintain good nutritional habits.
Another important note is the potential for more effective nutrient partitioning. When the body is not in an extreme caloric deficit, it may more effectively allocate nutrients toward muscle repair and growth, offering a dual benefit of fat loss and muscle retention .
From an endocrine standpoint, smaller deficits over longer periods are less likely to elicit stress responses, such as increased cortisol levels, which can further sabotage muscle retention and metabolic rate .
The Endocrine Impact of Larger Caloric Deficits
A critical consideration in the context of larger caloric deficits and metabolism is the influence on the endocrine system, specifically the interaction between the pituitary and thyroid glands. When confronted with a significant caloric deficit, the pituitary gland often decreases the secretion of Thyroid-Stimulating Hormone (TSH). This reduction can result in suppressed production of thyroid hormones T3 and T4, which are vital for maintaining metabolic rate .
A study in the “American Journal of Physiology” illustrates that even short-term caloric restriction can significantly alter T3 levels, indicating immediate metabolic adaptations . Another study published in the “Journal of Clinical Endocrinology & Metabolism” found that low-calorie diets led to a substantial decrease in T3 levels, impacting metabolic rate . These changes can be more severe with larger deficits than with smaller deficits sustained over a longer period. The larger caloric deficits can lead to a more significant reduction in thyroid hormones T3 and T4, which in turn affects metabolic rate. This is often observed as part of the body’s adaptive mechanisms to conserve energy during periods of significant caloric restriction [7.
Both dieting strategies have unique metabolic consequences. Longer periods with smaller deficits tend to have a less pronounced effect on the metabolic rate and high muscle retention, while shorter periods with larger deficits can lead to a more rapid metabolic slowdown, and less muscle retention. The latter may make subsequent Contest Preps more challenging, and time between prep longer due to the lingering effect of Metabolic Adaption resulting from an excessive deficit.
When choosing between long dieting periods with smaller deficits and shorter periods with larger deficits, consider not just the speed of weight loss but also the long-term metabolic consequences and the ability to preserve muscle mass. Both approaches have pros and cons, and the choice should be tailored to individual metabolic responses, the timeframe available, and the goals set for stage appearance or future preps.
 Fothergill, E., Guo, J., & Howard, L. (2016). Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. International Journal of Obesity.
 Redman LM, Heilbronn LK, Martin CK, de Jonge L, Williamson DA, Delany JP, Ravussin E; Pennington CALERIE Team. Metabolic and behavioral compensations in response to caloric restriction: implications for the maintenance of weight loss. PLoS One. 2009;4(2)
 Helms, E. R., Zinn, C., Rowlands, D. S., & Brown, S. R. (2014). A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Nutrition & Metabolism.
 Byrne S, McLean N. Elite athletes: effects of the pressure to be thin. J Sci Med Sport. 2002 Jun;5(2):80-94.
 Aragon, A. A., & Schoenfeld, B. J. (2013). Nutrient timing revisited: is there a post-exercise anabolic window? Journal of the International Society of Sports Nutrition.
 Hill, E. E., Zack, E., Battaglini, C., Viru, M., Viru, A., & Hackney, A. C. (2008). Exercise and circulating cortisol levels: the intensity threshold effect. Journal of Endocrinological Investigation.
 Samuels, M.H. (2008). Effects of variations in physiological cortisol levels on thyrotropin secretion in subjects with adrenal insufficiency: a clinical research center study. Journal of Clinical Endocrinology & Metabolism.
 Klieverik, L.P., Coomans, C.P., Endert, E., Sauerwein, H.P., Havekes, L.M., Voshol, P.J., Rensen, P.C.N., Romijn, J.A., & Kalsbeek, A. (2009). Thyroid Hormone Effects on Whole-Body Energy Homeostasis and Tissue-Specific Fatty Acid Uptake In Vivo. American Journal of Physiology.
 Spaulding, S.W., Chopra, I.J., Sherwin, R.S., & Lyall, S.S. (1976). Effect of caloric restriction and dietary composition of serum T3 and reverse T3 in man. Journal of Clinical Endocrinology & Metabolism.
Discover the transformative power of periodization in strength training, especially if you’re new to lifting. Learn about linear periodization, how it helps break through plateaus, and why it’s crucial for injury prevention. Practical tips and examples included.
To maximize the effectiveness of your training, it’s critical to understand the concentric and eccentric phases of muscle contraction. This in-depth guide will delve deeper into the science behind these phases, offering evidence-based insights from experts like Brad Schoenfeld and Mike Zourdos. Additionally, we’ll explore how to implement Daily Undulating Periodization (DUP) to achieve both strength and hypertrophy.
The Underlying Science
Hypertrophy and Eccentric Mechanics
One of the most important factors in muscle growth is the eccentric phase, where the muscle lengthens under tension. When compared to concentric actions, eccentric actions are unique in their ability to impose higher levels of mechanical tension on the muscle fibers. This mechanical tension triggers a cascade of cellular events leading to muscle hypertrophy.
In a study by Brad Schoenfeld, he elaborates on the greater recruitment of Type II muscle fibers during eccentric movements (Schoenfeld, 2010). These fibers, also known as fast-twitch fibers, have a greater propensity for growth because they contain more actin and myosin contractile proteins. This makes them especially susceptible to muscle damage, another significant driver for muscle repair and growth. Moreover, it’s during the recovery period post-damage that we see a spike in muscle protein synthesis rates, which is essential for hypertrophy.
Eccentric contractions also demonstrate higher force outputs at lower levels of metabolic stress, meaning that you can lift heavier loads more efficiently during the eccentric phase. This is particularly advantageous for hypertrophy, as research indicates that lifting heavier loads while maintaining a strong mind-muscle connection can maximize muscle activation and growth. Additionally, Schoenfeld’s studies indicate that eccentric training may elevate the levels of specific growth factors, like IGF-1, within the muscle, further contributing to the hypertrophic process.
Concentric Phase and Neural Adaptations
When it comes to strength gains, the focus shifts toward the concentric phase of muscle contraction, where the muscle shortens under load. During this phase, neural adaptations play a critical role. According to research by Brad Schoenfeld, lifting heavier loads during the concentric phase initiates a set of neural responses that enable you to produce greater force in subsequent contractions (Schoenfeld, 2017).
These neural adaptations include the increased synchronization of motor units and a more efficient recruitment pattern. What this means is that your nervous system learns to activate more muscle fibers simultaneously, thereby increasing the force generated by the muscle. Enhanced neural drive also allows for quicker activation of muscle fibers, particularly Type II fibers, which are essential for explosive movements and high-force outputs. This adaptative neural behavior makes it easier to handle heavier weights, progressively increasing your strength capacities over time.
The Symbiosis of Strength and Hypertrophy
The importance of strength training in hypertrophy cannot be overstated. Strength gains have a reciprocal effect on hypertrophy, as increasing your maximal strength allows you to lift heavier weights in the hypertrophy rep range. This essentially results in greater mechanical tension on the muscles, further amplifying muscle growth. Strength phases can act as potent catalysts for hypertrophy when integrated appropriately into your training regimen.
Periodization: The Best of Both Worlds?
In bodybuilding, periodization can be invaluable for both hypertrophy and strength gains. It allows you to focus on different aspects like maximal strength or hypertrophy during specific phases.
Hypertrophy Phase Example (5-day week):
- Monday: Chest and Triceps (8-12 reps at 65-75% 1RM)
- Tuesday: Back and Biceps (8-12 reps at 65-75% 1RM)
- Thursday: Legs and Shoulders (8-12 reps at 65-75% 1RM)
- Friday: Upper Body (8-12 reps at 65-75% 1RM)
- Saturday: Lower Body (8-12 reps at 65-75% 1RM)
Strength Phase Example (4-day week):
- Monday: Chest and Triceps Focus (5-7 reps at 80-85% 1RM)
- Wednesday: Back and Biceps Focus (5-7 reps at 80-85% 1RM)
- Friday: Legs and Shoulders Focus (5-7 reps at 80-85% 1RM)
- Sunday: Full-Body Strength (5-7 reps at 80-85% 1RM)
Daily Undulating Periodization (DUP)
Daily Undulating Periodization (DUP) by Mike Zourdos offers an integrated approach where you rotate between different rep and intensity schemes within the same week, targeting both hypertrophy and strength (Zourdos, 2016).
For example (5-day week):
- Monday: Strength Focus, Lower Body (5-7 reps at 80-85% 1RM)
- Tuesday: Strength Focus, Upper Body (5-7 reps at 80-85% 1RM)
- Thursday: Hypertrophy, Chest and Triceps (8-12 reps at 65-75% 1RM)
- Friday: Hypertrophy Focus, Legs and Shoulders (8-12 reps at 65-75% 1RM)
- Saturday: Hypertrophy Focus, Back and Biceps (8-12 reps at 65-75% 1RM)
Bodybuilding success hinges on a nuanced understanding of the mechanics of muscle contraction, particularly the concentric and eccentric phases. By carefully integrating strength and hypertrophy training, utilizing periodization, and taking a scientific approach to exercise selection and execution, you can optimize muscle growth and performance. Daily Undulating Periodization (DUP) offers a flexible, evidence-based framework that allows you to achieve the best of both worlds, setting you on a path to becoming a more complete bodybuilder.
- Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 31(10), 2857-2872.
- Schoenfeld, B. J. (2017). Strength and hypertrophy adaptations between low- vs. high-load resistance training: A systematic review and meta-analysis. Journal of Strength and Conditioning Research, 32(12), 3508-3523.
- Zourdos, M, et al. (2016). Modified Daily Undulating Periodization Model Produces Greater Performance Than a Traditional Configuration in Powerlifters. J Strength Cond Res. 2016 Mar;30(3):784-91
One of the most common skin concerns people have is cellulite, the pesky, dimpled appearance on the skin that’s often compared to orange peel or cottage cheese. Despite the numerous products and procedures claiming to banish cellulite, there’s no one-size-fits-all solution. We aim to unravel the complex anatomy and factors behind cellulite, specifically focusing on the role of septae, to give you a better understanding of what works, what doesn’t, and why.
The Anatomy of Cellulite: Understanding Septae
Septae are fibrous connective tissues that anchor the skin to the underlying muscle layer. They partition the fat beneath the skin into pockets filled with fat cells, also known as adipocytes. When these adipocytes swell due to an accumulation of triglycerides, the result is tension between the skin and septae, creating the familiar dimpled appearance known as cellulite. In simpler terms, think of the fat cells as balloons filling up with air (triglycerides), and the septae as cords that hold these balloons in place. If the balloons expand but are restricted by the cords, the result is a lumpy skin surface.
Genetics and Cellulite: Can You Really Blame Your Parents?
Genetic factors significantly influence the structure, thickness, and elasticity of the septae, making some people more predisposed to visible cellulite than others. Variables like skin thickness and elasticity, both influenced by genetics, can either minimize or exaggerate the appearance of cellulite. Additionally, hormones like estrogen are another reason why women are generally more prone to cellulite than men.
Lifestyle Choices and Cellulite Appearance
While you can’t alter your genetic makeup, you have control over lifestyle choices that can affect cellulite. Higher levels of body fat exacerbate the pressure against the septae, making cellulite more visible. On the flip side, lowering your body fat through a balanced diet and regular exercise can alleviate this tension and potentially lessen the appearance of cellulite.
Treatment Options: A Glimpse into Solutions
There are multiple treatments targeting the septae to improve the appearance of cellulite. These include surgical procedures like subcision, which severs the septae bands to allow the skin to spring back to a smoother appearance. Other options involve radiofrequency, laser treatments, and high-frequency ultrasound that aim to either break down the septae or stimulate collagen production to improve skin elasticity. However, be cautious when exploring these options as they can be costly, and their effectiveness varies.
Navigating the Marketing Maze
A variety of products and treatments claim to miraculously reduce cellulite. These range from creams to specialized garments like anti-cellulite leggings. It’s crucial to approach these claims skeptically for several reasons:
- Limited Scientific Backing: Many of these treatments are not rigorously scientifically verified.
- Cost Factor: Most treatments can be quite expensive, especially those requiring multiple sessions.
- Safety Concerns: Some treatments have potential side effects, making it essential to consult healthcare providers for personalized advice.
Cellulite is a complex skin condition influenced by a combination of genetic and lifestyle factors. While certain treatments focus on the role of septae in cellulite formation, it’s essential to approach these options critically, considering their cost, efficacy, and potential side effects. Lifestyle adjustments like regular exercise and a balanced diet remain the most universally beneficial and low-risk methods for managing cellulite’s appearance. Being informed is the first step in making the best choices for your skin and body.