It seems the whole world is currently on a low carb diet of some variation or another. For some carbohydrates have become the spawn of evil, responsible for every ailment going. For others low carb diets have been seen as the only way to decrease bodyfat.
As a bodybuilder who wishes to be lean its easy to get caught in the trap of believing low carb is the way to go in pursuit of a ripped physique.
Hopefully by the end of this article you will have a more rounded view on carbohydrates and if you still want to follow the low carb route for fat loss I should be able to show you a plan that will at least negate some of the negative elements of low carbing.
Initially I'm going to side with the low carb fanatics and concede a few positive points of reducing or eliminating carbohydrates - but don't get fooled into a false sense of security I fully intend to highlight the downfalls (and there's a lot!).
Low Carb Benefits
:: Although it pains me to say.
Reduced Insulin Levels:
Lowering Carbohydrates or eliminating them will decrease the amount of circulating insulin within the plasma. Lowered
insulin levels creates an environment in which fat is more readily liberated from there storage sites (adipocytes).
Basically Insulin is a gate way hormone that actively transports glucose, amino acids and triglycerides (fats) into the various cells of the body including muscle and adipocytes. Considering insulin's main function is to drive nutrients into cells, it would seem obvious that hormones that liberate fat would be suppressed (otherwise your body would be constantly opposing itself).
Lipid Meal Shifts Metabolism:
Eating a high fat and
low carbohydrate meal produces the same response as three to four days of
fasting. Basically the body shifts from carbohydrate
metabolism to an increased fat metabolism, as carbohydrate oxidation, glycogen utilization and glucose turnover decreases.
It is evident that certain lipid metabolites play an inhibitory role on carbohydrate utilization as well as decreasing glucose uptake. When all this is considered it's clear that constantly reducing carbs throughout the day will shift the body into a fat burning mode, making it easier to access the stored bodyfat you wish to get rid of.
Restricts Food Choices:
Lets be honest low carb diets are restrictive in that a whole lot of different foods contain
carbohydrates. In fact if you are following a fairly zero carb diet policy you will have to cut out whole food groups.
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Considering that you are restricting food choices it shouldn't surprise you that you will inevitably restrict overall calorie intake. Even if you love meat and other low carb foods your body will soon get tired of eating the same thing and create high levels of satiety within the brain.
This is sometimes termed sensory specific satiety, basically you become full on one taste of food but offered something else and you probably could carry on eating.
Considering that the food choices are more limited on a low carb diet you will not have as much opportunity to over indulge in a variety of tastes and therefore will be more likely to eat less and put yourself in a hypocaloric state regardless of the macronutrients.
Cons Of Low Carbing
Fat Burns In A Carbohydrate Flame:
For fat to be burned it has to go through the metabolic processes within the mitochondria within the muscle. During the aerobic metabolism of fat several step wise processes have to occur.
A carbohydrate byproduct (oxaloacetate) acts as primer for this metabolic reaction. Obviously severely reduced glycogen levels as seen during low carbohydrate diets will affect the levels of oxaloacetate and consequently the metabolic process of fat utilization.
Intensity Is Reduced:
Low carbohydrate diets will deplete glycogen levels as your body will have to switch to ketones for energy. Clearly lowered glycogen levels will have a marked effect on your physical performance within the gym. Depleted glycogen levels will decrease the workload you can perform both during resistance training and
Reduced workload during resistance training will mean less recruitment and exhaustion of muscle fibres, and therefore fewer gains seen or less retention of muscle if you are strictly dieting.
Like wise reduced workload during cardiovascular exercise will result in less total calories burnt and consequently less overall fat burnt for any given period exercising.
Many proponents of low carb diets suggest the results seen in studies showing decreased physical performance ignore a time lag that it takes for your body to become used to fat metabolism. This is still equivocal.
Reduced Fiber & Micronutrients:
Low carbohydrate diets require the restriction of most sources of fiber within the diet as sources of fiber/NSP (non starch polysaccharides) also contain a fair degree of carbohydrates. Along with this comes a possible reduction in micronutrients (
vitamins and minerals) as most fibrous sources of carbohydrate also provide their fair share of micronutrients.
Considering that a lot of vitamins act as coenzymes for bodily functions including energy metabolism and cell construction, it would seem obvious that reduced levels of micronutrients would hamper physical development.
Hypoglycemia & Lowered Testosterone Levels:
Although fat and cholesterol are vital nutrients in the production of anabolic hormones such as
testosterone, it has been shown that a chronic hypoglycemic state through severe carbohydrate restriction reduces the amount of Luitenizing hormone produced and consequently a reduced testosterone level.
Obviously a reduced level of testosterone will impair the adaptive response of your exercise.
Glycogen Levels & BC Oxoacid Dehydrogenase:
Low glycogen levels result in the body trying to liberate energy else where, namely fat and the muscle itself! As glycogen levels fall an enzyme is produced (BC oxoacid dehydrogenase) which breaks down the branched chain amino acids from your muscle to use as fuel.
Considering this low carbohydrate diets will constantly put you in a state of catabolism as the body tries to use some other fuel instead of the glucose usually stored and circulating.
A rise in BC oxoacid dehydrogenase has also been cited as a cause of central fatigue (inability of the nervous system to optimally transmit signals to the working muscles) as branched chain amino acids competitively inhibit uptake of tryptophan which goes on to become serotonin.
Recommendations For Reduced Carb Dieters
Considering there are both positive and negative consequences to reducing carbohydrates a happy medium is needed. I personally prefer to manipulate carbohydrate levels throughout the day to minimize lipogenic effect of insulin and maximize the anabolic response circa workout time but that's a whole article in itself.
Instead I will just suggest ways of decreasing the negative aspects of low carb dieting for all you ketogenic fanatics.
- Never go more than three days without having a high carbohydrate day. This in essence ensures you follow a cyclic ketogenic diet. Over the three days you will tap into all the benefits of a low carb diet but your glycogen levels will have reduced dramatically. The high carb day ensures your glycogen levels are restored and you will have offset a lot of the negative consequences over the next prevailing three days of low carbing.
Don't concern yourself about the carbohydrates undoing the fat loss benefits of the previous three days. Because your glycogen levels are low your insulin sensitivity will be sky high and any carbohydrate will just be stored as glycogen.
- Try to ensure what little carbs you have on low carb diet are either fibrous sources (i.e. vegetables) throughout the day or simple sugars immediately post workout. Obviously this depends on what your classification of low carb dieting is. For some low carb dieting is only going down to one gram per pound of bodyweight.
For the more fanatic ketogenic followers a maximum of twenty grams of carbs per day is their upper limit. The lower you go the more important it will become to have high carbohydrate refeeds throughout the week to restore glycogen levels.
A second function of glutamine during low carb dieting would be its ability to offset the possible metabolic acidosis that is common when dropping the carbs. It does this through its ability to accept hydrogen ions. This is even more important for the very low carb diets as fruits and vegetables usually provide alkaline compounds which will offset any metabolic acidosis, but obviously on a very restricted low carb diet these will be somewhat absent.
- Supplementation of dietary fiber and micronutrients is essential during low carb periods. A good fiber supplement will help you attain the thirty five grams of fiber daily recommended for optimal health and should limit the bowel clogging effects most report when ditching the carbs.
Although a vitamin and mineral supplement have their down falls (nutrient interactions effecting absorption and a lack of many minor nutrients we currently know vary little about) they will be better than going without.
For all of you ketogenic enthusiasts some of what I said will be heresy, but if you want to get the most from your training and dieting you need to take into account the positive impact that carbs can have. Use the advice above and you get to have your cake and eat it (I couldn't resist the pun for all you dieters out there, sorry)