In my experience, CR is as good as the body can avoid marked catabolization while on it. Sustained or even intermittent significant muscle wasting (even if sub-clinical) isn't a marker of improving health. Additionally, hunger does not act as a pressure that will lead to an adaptive rest of your system's homeostasis. Most often, hunger as well as random calorie restriction (frequent small meals) leads to minimal, if any, improvement in anabolic response or other relevant improvements other than in BMI and the loss of obesity related pathology.
Improperly conducted, CR can damage the health of the system in a short time. Your hormonal profile and other markers won't improve if your body is in starvation mode, despite how the CR studies are often mistakenly interpreted. I know this from experience. Blood sugar needs to stay even while on CR. My primary reason for writing this is to warn CR aspirants off of what will likely be an unfruitful and potentially harmful (as in you will likely accelerate the aging process) practice.
Hunger shouldn't be present past the first day of adjustment, because that signals an energy deficit that causes the release of counter-productive hormones into the blood. Cortisol increases blood glucose from muscle catabilzation. You don't want to increase glucose at any time in-between meals, even endogenously (this has happened if you power through hunger to the point where youa re no longer hungry). CR doesn't work because of an energy deficit but because of the extended period in-between meals (in my decade of experience with it). The mechanism isn't clear, but it does clearly extend past the simple concept of calorie restriction that causes one to ignore other factors that are likely crucial to an any truly significant response. Those factors include meal frequency, liquid intake rhythm, thirst, sleep rhythms, stomach and gut bacteria physiology in response to food/liquid intake rhthyms, and more. Remember, humans have to live and function on CR. We aren't mice. We need an optimal response out of a process that doesn't leave us incompacitated or demoralized. Simply restricting calories haphazardly, even when steering clear of pathology, doesn't give enough of a response for the mental/physical pain and trouble. It's not worthwhile, and that's before considering the potential risk.
In my expreience, the trick is to extend the period in-between meals while keeping blood sugar steady. The longer the period in-between meals (including putting anything in your mouth) while maintaining steady blood sugar, the more semi-permanent result you will feel (I say semi because bad habits and aging without continued practice can reverse all results). My felt results from a single successful 24 hour period will last a couple of weeks. Don't concentrate on daily calories or meal calories, but on the time in-between meals and felt energy homeostasis (not feeling hungy or thirsty for significant periods of time). There are tricks to this. Once you extend the time in-between meals enough, the time/calorie ratio will assure low calorie intake even if your meals are high calorie. Once you get good enough, you won't need high calorie meals because your insulin sensitivity will reset. Don't be afraid of high calorie meals. Watching calories is putting the cart before the horse. You are attempting to cause a dramatic change in energy homeostasis. Calories (and their macronutrient container) are the primary signal that you use to communicate with your system and instigate change, along with liquid intake (also crucial to master to be successful in the CR process ). Manipulating the signal causes changes, and that signal can be manipulated in a variety of ways other than just reducing calories. If you limit yourself to just strict calorie reduction, while ignoring all of the other ways in which calories can be used to manage and control your energy homeostasis, then you won't be successful. Sometimes a lot of calories are necessary after an extended period in-between meals, especially in the beginning. If you are extending the time in-between meals, the meals should be high in complex carbohydrates. I like white rice for this purpose. Fat has a role as well, but it's different than the glucose storage role you will need a large intermittent meal to play. If all relevant factors are not successfully addressed then failure will likely result. What leads to fasting failure? How do you mitigate that? How can you avoid what triggered the hormonal cascade that led to failure? Your body will become vastly more sensitive during the first two days of a fast. Learning how to mitigate and control your body's hormonal responses is the key to pushing through the difficult time, minimizing the difficult time, and quickly reforming the homeostatic setpoints of your mind and body.
Successful CR is a complex undertaking that can and will most often be unsuccessfully implemented. It took me 7 long years to master. I kept a detailed journal of my technique the entire time, and only got to the correct effective technique after all of those years of trial and error. I would start, go as long as I could until I had to abort, and then adjust the method. At one point early on (the first three years or so), I went 5 days without significant food (2-3 egg yolks per day - not currently recommended as a calorie source) or water (any), while working, and was fine (defined as no felt muscle catabolism or energy deficit). That isn't necessary to get results (although I did get results), and is actually counter productive. Now, I can get much better results in 1-2 days because I learned how to more effectively signal my brain to change. My point is that I went through a long process of getting to know the responses of my mind and body to cycles of feeding, drinking, sleeping, and calorie restriction. Knowing every little response, and how to handle it successfully, is crucial and can't be taught on a forum. Experience is needed. You should FEEL the hormonal benefit within the first week. If not, you're doing it wrong and are likely even doing damage. Energy balance is a delicate and dangerous thing to mess with. Even if I were to instruct someone in-person, it would take months of their own trial and error before they were used to their responses and how to handle them successfully. Nuanced feelings and responses are king when your body becomes ultra-sensitive after the first 18-24 hours or so. Experience instructs your decisions that will push you further into success or to abort the process and start again. Repeated failure is absolutely necessary.
My belabored, opaque rant above is supposed to serve two purposes. 1. It is suppsoed to convey a little bit of the complexity involved in successfully implementing CR to true success. 2. It is supposed to act as a deterrent to that process, if committment to it is to be limited to a casual calorie reduction that will be undoubtedly plagued with periods of hunger/weakness. It's at once impossible to convey my technique and impossible to not give (yes a double negative) seemingly detailed info that will, perhaps, assure readers that I know what I'm talking about. I recommend life extension methods other than CR. You aren't a mouse and so, in my opinion, it isn't practical. I only got as far as I did because, health wise, I felt as if I didn't have a choice (this was before I knew about longecity). I surmise that it would take the same level of desperate motivation to push someone through the same process.
Edited by golgi1, 10 July 2014 - 07:39 AM.