Diet Discovery

I’ve heard that people on low-carb diets start out feeling without energy, because the body is still accustomed to providing energy through glycolycis, but later in the diet have plenty of energy to spare. If it’s not glycolysis that’s providing the energy(how could it be, where is the glucose) then what is it?

Glucose provides quick energy but dietary fats provide sustained energy. Coconut oil if the only fat that provides quick energy just like a carb but without insulin or blood sugar reactions.

The core of Atkins program is converting the body from glycolysis (burning glucose as fuel) to ketosis (burning fat as fuel). Dietary fat levels need to be at >65% of total calories, if not, the body will still remain in glycolysis by converting 58% of excess protein into glucose (via gluconeogenesis).

Glucose is the bodies preferred fuel (if you want to get technical, it actually burns alcohol most efficiently, but that doesn’t make it any healthier for the body than carbs), the body can convert 100% of carbs, 58% of protein & 10% of dietary fat into glucose. The body can also be fueled by fat (dietary fat & fat cells) but only in the absence of carbs. Your brain actually prefers* to be fueled by ketones (part of the fat burning process), it does require glucose also, but glucose can be easily converted from excess protein if needed or dietary fat.

I think that ketosis is not the back up fuel plan. I think ketosis was meant to be primary fuel plan, that is easily overridden (one bite) by ingestion of carbs (or alcohol). The body is rarely allowed to become fully fat adapted, especially in these days of people using processed food formula to feed infants instead of breast milk. Carbs were never supposed to be available year around, only seasonally during harvest. The body can easily handle carbs even in excess occasionally, just not continuously. The body can also be fueled by protein (via gluconeogenesis) but long term protein synthesis creates the byproducts of ammonia & nitrogen. The body can easily handle clearing out these byproducts but if gluconeogenesis is used as the primary fuel source for long term, the body can be overwhelmed (poisoned) by the excess ammonia & nitrogen. It’s all contingent on balance but the body functions at optimal levels on more dietary fat & suboptimal levels on less dietary fat.

The body always has the ability to use ketone bodies as fuel. Even people in glycolysis (except those that are hyperinsulimic) burn some fat as they sleep, this helps preserve glycogen stores. Using fat as fuel & being fueled by fat are the difference in the body becoming fully fat adaped to being fueled by ketone bodies & glycerol.

This study done on athletes in training during the conversion process says that after one has become fat adapted, endurance exercise performance returns to normal.:

http://www.nutritionandmetabolism.com/content/1/1/2

I highly recommend low carb way of eating for optimal health. It takes 3-6 weeks for the body to become fully fat adapted to perform athletically but the body does convert *if* carb cycling is not used. Athletes studied said their performance was effected the first week or so but recovered to full athletic ability within a few weeks.

For bodybuilders, low carb creates lean tissues even without working out, working out should create even more muscle mass. When insulin dominates the blood stream, testosterone & human growth hormone (HGH) aren’t produced, which are both anabolic hormones & contribute to muscle growth. Excess protein is converted to glucose *unless* dietary fat levels are greater than 80% of dietary calories, then I believe that excess protein is forced to create lean tissues (just as excess carbohydrates are forced to create fat tissues).

Marathon athletes aren’t restricted to glycogen stores. Athletes in glycolysis (using glucose for fuel) have to "carb load" to fill glycogen stores but athletes in ketosis (using fat for fuel) don’t have these restrictions. A normal weighted person has enough fat stores to run for more than 200 hours – glycogen stores only last a few hours before being depleted & the athlete "hits the wall"

Carb cycling programs never allow the body to become fully fat adapted, which I believe takes 3-6 weeks. The metabolism just shuts down & awaits a return to glycolysis.

^ In glycolysis, the brain requires 120g of glucose per day, but the brain gets its energy from ketone bodies when insufficient glucose is available. After blood glucose is lowered for 3 days, the brain gets 30% of its energy from ketone bodies. After 40 days, this goes up to 70% (during the initial stages the brain does not burn ketones, since they are an important substrate for lipid synthesis in the brain). In time the brain reduces its glucose requirements from 120g to 10g per day (with ketones & glycerol providing the difference).

Ketones have been described as "magic" in their ability to increase metabolic efficiency, while decreasing production of free radicals, the damaging byproducts of normal metabolism. The heart and brain operate 25% more efficiently using ketones as a source of energy

http://en.wikipedia.org/wiki/Ketone