Hello again and it's time for weigh in. The cheating seems to have edged up a bit in the last week so I want to remind everyone that cheating is a really bad idea and will hinder your weight loss. It's called Bootcamp for a reason. We only want ten weeks from you and the cheat foods will still be there at the end of Bootcamp. But for now no cheats please. Next time you're tempted remember it isn't the last scone/cake/wine in the world.
If you need a reminder or you're joining Bootcamp partway through, the rules are on the Spreadsheet of Fabulousness and you can also track your weight on the Weight Tracker.
As promised last week I've written some info on the science behind diets...
How do we lose weight?
First, why don't low fat restricted calorie diets work? It comes down to homeostasis: our bodies actively resist change. For some reason in humans our resistance to weight change appears to be asymmetric, that is we resist losing weight much more effectively than we resist gaining weight. Most of us have experienced first hand the gradual increase in weight over time, or the more abrupt but still unshiftable weight gain that happens with pregnancy. Basically it's easy to gain weight but difficult to lose weight. So we go on a reduced calorie diet, eating 1800 calories while our bodies are expending 2000 calories. We may lose some weight at first but eventually eating 1800 calories becomes the norm and our bodies resist the change by dropping the metabolic rate to match calorie output to input. But, and here's the problem, the metabolic rate might drop to reduce calorie expenditure by 300 calories rather than 200 in order to regain the lost weight and get back to our normal weight. So weight loss stops, we get disheartened and quit the diet and our reduced metabolic rate allows the weight to pile back on and then some, just in case we encounter this artificial famine again in the future.
So what's different about a low carb diet? One of the key rules of Bootcamp is to eat when you're hungry. This works to prevent the reduced metabolic rate that scuppers a reduced calorie diet. When you start eating a low carb diet and you have exhausted your glycogen stores, the liver starts converting fat from your diet into ketones. Your muscles start using ketones and then adapt to using fatty acids for energy. Your brain uses ketones and glucose from your diet along with glucose produced from protein by gluconeogenesis. The low levels of insulin induced by a low carb diet allow fatty acids to flow freely in and out of fat cells. It is this free flow of fatty acids from your fat cells that allows you to lose weight on a low carb diet without restricting calories. Your muscles cannot distinguish whether fatty acids came directly from your digestive system or from your fat cells, they just use them up as needed. As you adapt to the low carb diet, there is a reduction in your appetite in response to the ready availability of energy at all times. A low carb diet works simply by allowing your muscles and liver to freely use fatty acids released from your fat cells.
Good luck for the coming week. Keep on keeping on.