By: Dave Asprey. John Kiefer is an exercise scientist, nutrition expert, and author of the new book Carb Back-Loading. John applies his knowledge from a career in physics to hack the human body for fat loss, muscle gain, and improved performance. He is the author of the Carb-Nite Solution, and is releasing a new book that is designed for rapid fat loss and muscle gain. John is coming on Bulletproof Executive Radio to help you do what some people call alchemy — burning fat and building muscle at the same time. Podcast: Play in new window Download.
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The premise behind CBL basically revolves around taking advantage of the supposed fluctuations in insulin sensitivity IS within the muscle and fat tissue throughout the day, as well as the non-insulin mediated uptake of glucose within the exercised muscles. For example, insulin sensitivity in both muscle and fat tissue is generally higher in the morning relative to the evening.
Therefore, Kiefer suggests that a way to get around this problem would be to train in the evenings as well as consuming almost all of your daily carbohydrate post-workout PWO , whilst eating as little carbs as possible throughout the day. That way, you would supposedly take advantage of the reduced insulin sensitivity in fat tissue in the evenings, but also have the benefits of increased insulin sensitivity more specifically, non-insulin mediated uptake of glucose in the muscles PWO due to the evening training.
In addition, by avoiding carbs as much as possible during the day when overall IS is high , fat gain via de novo lipogenesis the creation of new fat tissue via carbohydrate , would apparently be minimised.
Overall, this would hypothetically result in the potential for successful body recomposition i. Because of the relative complexity of CBL, it seems to be suitable for the intermediate-advanced weight trainees as opposed to beginners.
Before moving onto the more critical aspects of this review, I do actually think that there are some positives that we can take away from CBL and it would be biased of me not to include them.
Firstly, CBL is good for those who like to eat crap but still want to be reasonably lean. By focusing on carbohydrate consumption in the evenings, CBL also nicely destroys the myth about not eating carbs after 6pm or some other random time.
Although, at the same, it creates worry about eating carbs in the AM! CBL is also good if it fits nicely with your current lifestyle i. Perhaps another positive aspect of CBL is that it attempts to be evidence-based, and in doing so Kiefer cites 48 pages of references to support his points. He also highlights a few common misunderstandings that are prevalent in the fitness community, such as the fact that some types of fibre DO have an energy value the type that can be fermented in the colon to produce short-chain fatty acids , as well as making the distinction between non-insulin dependent glucose uptake via GLUT4 translocation and insulin sensitivity per se concepts that people often use interchangeably.
Finally, and perhaps most importantly, the general premise of CBL i. Specifically, I will only look at randomised-control trials RCTs , since this is the only type of research that can establish cause and effect. There are correlational data signifying associations between shifting the intake of calories at different times of the day and adiposity. However, given the observational nature of such studies, which are confounded by a plethora of uncontrolled variables, they cannot establish cause and effect.
As such, they are useful for generating hypotheses to be tested under controlled conditions, but drawing conclusions from this type of data is erroneous perhaps someone should tell science journalists this. The whole idea of shifting carbohydrate intake to later in the day is largely based on two studies, which are frequently cited throughout CBL. The first study by Keim et al. It was found that the ingestion of the larger AM meals resulted in greater weight loss compared with the larger PM intake, but this extra weight loss consisted of lean body mass LBM.
Therefore, the consumption of larger PM meals resulted in greater preservation of lean body mass LBM and resulted in a greater reduction of fat mass see table below. This study possessed several design strengths, the most notable of which was that it was conducted in a metabolic ward, meaning that food intake was strictly controlled.
Furthermore, the 10 women underwent a structured exercise programme consisting of cardio and resistance training, making the results somewhat more applicable for those implementing CBL. However, two notable limitations of this study include the relatively small sample size 10 and method of assessing body composition total body electrical conductivity, which is similar to BIA.
The more recent trial used to support the evening carb intake of CBL is a 6-month study by Sofer et al , in which the authors compared the effects of carbs eaten mostly at dinner vs. It was found that reductions in weight, body fat and waist circumference were greater in the evening-carb experimental condition vs.
In addition, glucose control, inflammation, blood lipids and satiety were improved to a greater degree in the evening-carb group. Moreover, leptin levels decreased to a lesser degree in the experimental condition and may partially explain the better maintenance in satiety within this group, as well as the greater observed weight loss.
It is possible that the greater reductions in satiety in the control group led to a greater caloric intake in comparison to the evening-carb group, and thus explaining the more favorable body composition results seen in the experimental group.
Although this study looks extremely promising for CBL with respect to all the anthropometric, hormonal and biomarker data, the methodological limitations of the investigation are worth briefly discussing. Whilst a specified diet was prescribed, dietary intake was self-reported unlike the shorter trial above. As the participants in this trial had an average body mass of This intake is below that required to spare muscle mass and promote satiety and is far below that typically consumed by weight trainees looking to improve body composition.
Therefore, the study's relevance to such populations is questionable not to mention the lack of a structured exercise programme. Finally, when we look at the differences in weight loss between groups, the experimental group lost 2. For those with more than a passing interest in the topic, Martin Berkhan of LeanGains does an excellent job of reviewing these studies.
Due to their neutral findings, these studies tend not to be mentioned by CBL advocates. Though, by the weight of the limited controlled evidence, it does seem that shifting caloric and carbohydrate intake to later in the day would provide a SLIGHT benefit with respect to body composition, hormonal changes and makers of health and disease.
Click here for part 2. Joseph Agu, MSc. Michael Johnston, PhD. What is Carb Back-Loading? This may include skipping breakfast. Keep carbs at an absolute minimum throughout the day until training. Train in the afternoon, at around 5pm or so. Start ingesting carbs after your training session, up to 30 minutes later. Continue eating carbs throughout the night. The strengths of CBL. Does research support the idea of CBL?
An Objective Review of John
John Kiefer: Carb Backloading, Insulin Hacking, and Dropping 100 Pounds with Ice Cream
The premise behind CBL basically revolves around taking advantage of the supposed fluctuations in insulin sensitivity IS within the muscle and fat tissue throughout the day, as well as the non-insulin mediated uptake of glucose within the exercised muscles. For example, insulin sensitivity in both muscle and fat tissue is generally higher in the morning relative to the evening. Therefore, Kiefer suggests that a way to get around this problem would be to train in the evenings as well as consuming almost all of your daily carbohydrate post-workout PWO , whilst eating as little carbs as possible throughout the day. That way, you would supposedly take advantage of the reduced insulin sensitivity in fat tissue in the evenings, but also have the benefits of increased insulin sensitivity more specifically, non-insulin mediated uptake of glucose in the muscles PWO due to the evening training.
John Kiefer: Carb Back-Loading – #19
Like so many other pioneers in this industry, selling is not my business: doing is. I did. I watched everything I put in my mouth and my eating schedule displayed Swiss-precision timing. I would never eat the foods I loved — like the cherry turnover above — and I never dared miss a feeding, fearing the rumble, irritability and nausea of an empty stomach. In short…. My background as a physicist keeps me hungry for knowledge. I stumbled upon an integral component of the way to stay lean and enhance every aspect of training — strength, size, aesthetics — with almost no effort.