When you start low carbohydrate high protein diet, the net metabolic effect is complex. Without going into great details about the actual biochemical processes the end results are:
- remember our discussion about potential elimination of bad carbs from our diet? Low carb diet takes this theory and implements it in real life all the way to extreme by minimising not only bad carbohydrates, but also by minimising even good carbohydrates, like fruits and some healthy vegetables as well. And guess what, it works, the appetite does get suppressed dramatically and food cravings do improve
- our body needs glucose as a primary source of energy, especially for the brain and to lesser degree muscles. In the absence of dietary carbohydrates, fat and proteins are converted into carbohydrates via gluconeogenesis, using a lot of energy while doing that
- another "energy wasting" process- around 25-30% of energy derived from digestion of proteins is being wasted as a "thermal effect"
- the body switches seamlessly to using ketones (products of degradation of proteins and fats) as a main source of energy instead of carbohydrates
- as body switches to ketotic state, when the energy derived from consumed proteins and fats is exhausted, it relatively easily switches to using the stored fat reserves as a source for energy and gluconeogenesis, resulting in relatively effortless weight loss
-there is always a risk that it might also use your own proteins as a source of energy, resulting in some muscle loss. This process is debatable and there some scientists who believe that such process might in some cases be even beneficial in "rejuvenation" of the old proteins
-at the beginning of low carbohydrate diet the body will use the natural carbohydrate reserves first - the glycogen. An average adult stores around 500 grams within the natural carbohydrates stores, around 100 grams within a liver and another 400 grams with the skeletal muscles. This is a human variant of "carbohydrate rechargeable battery", another way to store energy in addition to our bigger and more difficult to mobilize "fat accumulator". It does seem that first we need to drain this smaller "glycogen rechargeable battery" before we get to using our fats as a source of energy. One gram of glycogen holds three to four grams of water. That explains a rather sudden weight loss at the beginning of low carb diet. As we exhaust the glycogen stores, dietary fat and proteins are converted into glucose and eventually help to regenerate the glycogen, after further dietary restrictions, body fat starts to get mobilized to get converted into glucose to supple the "glycogen battery".
-after you initiate a low carb diet you might notice a significant increase in the amount of urine produced. At the beginning it will be water liberated after the glycogen metabolism. But as the body starts using the fat reserves as a source of energy, the final result of fat degradation are CO2 and H2O (water) which will result in increase of urination as well
-brain loves glucose as a main source of energy. Over time it might switch to ketones as an energy source but it might be very variable process from person to person. Headaches, decreased concentration, low energy are some of the common side effects of the low carb diet. Do not go on low carb diet when the brain sharpness is a priority (exams, job interviews etc.)
-being on low carb diet for extended period of time is like using a poor gasoline in the car - a lot of energy is being wasted. The body does a lot of unnecessary work to function while in low carb diet state. It is very effective to shed off few extra pounds, but I do not think it is not a healthy diet to stay for extended periods of time. I think it should be rotated with vegetable and fruit days as described in Rotating Diet Days.
- it is the best way to deal with uncontrolled food cravings. I compare this diet to "hard reset button" for your PC
-WHO officially listed read meats in category 2A as "probably cancerogenic to humans" (means there is limited evidence) and processed meats in category 1 as "cancerogenic" (means there is sufficient evidence). Both tobacco smoking and asbestos are listed in category 1 as well.