Some terms to know:
The measure of how quickly a food is converted to glucose (the simple sugar used for fuel) by the body. In general, simple carbs are converted much more rapidly than fat or protein. A rush of glucose leads to a release of insulin by the body (see “Insulin Resistance”, below). In structuring eating for fat loss, it is wise to avoid meals of simple carbs alone, and to combine carbs with fat and protein to slow conversion.
This isn’t a bad tool but it can be misleading. Some foods that are actually quite high in processed sugar score low on the GI. Fructose in particular scores very low, simply because it’s absorbed differently in the body.
From the journal Clinical Exp. Hypertension:
Insulin is the hormone that the pancreas produces to regulate the metabolization of carbohydrates. When we consume foods that contain carbohydrate energy (which makes up the bulk of most diets), our body turns it into simple glucides or sugars that are efficient sources of energy. These enter the blood, whereupon insulin is released to stimulate muscle cells to bring the glucose inside and store it as an energy reserve. When a body’s cells fail to respond adequately to the signals of insulin, an individual is said to be insulin resistant. Often, to compensate for the reduced action of glucose, the pancreas will produce more of it than would normally be necessary, and it will linger in the blood in higher concentrations. This is known as hyperinsulinemia. These two conditions, which tend to go together, are often but not always precursors of diabetes, which could be described as chronic dysfunction of glucose metabolism. Study after study has revealed an unusually high prevalence of both conditions among people with high blood pressure, and particularly among hypertensive people who are also overweight. Insulin is also linked to myocardial infarction (the most common form of heart attack) and microalbuminuria (the wastage of proteins in urine, a common kidney complication of hypertension as well as diabetes).
From Hyperinsulinism: The Metabolic Trap in Resistant Obesity (Calvin Ezrin, 1995)
Insulin controls fat build-up and breakdown as well as salt and water retention. It is the fat-building hormones generating triglycerides from carbohydrate precursors in the liver and also in adipose tissue where they are stored as energy reserves. Insulin also blocks fat breakdown via inhibition of the lipolytic action of growth hormone, glucagon, and catecholamines on the hormone sensitive lipase in adipocytes.
People with insulin resistance tend to be overweight, and to benefit from reducing the carbs in their diet.
The near-complete absence of carbs. A very strict diet. It works, but it’s not for the faint of heart or those who require variety and choice in their eating. It works well for people who prefer to eat a limited range of foods. Contrary to popular opinion, you can’t eat anything you want on a ketogenic diet. You have to eat fewer calories than you burn, otherwise you won’t lose any fat. Ketogenic diets are also used to treat children with epilepsy. Lyle McDonald wrote The Book on keto dieting, based on substantial research and his own experiences with it.
There are two kinds of ketosis: ketosis-lipolysis and ketosis-acidosis, and hand-wringing over ketogenic diets usually starts from confusing the two. When the body does not have any glucose available, as in a diet which eliminates carbohydrates, it manufactures another fuel from fat, and uses ketones as the fuel delivery system. To use the fat for fuel, the body breaks it down into glycerol and free fatty acids, which then break down into couplings of two-carbon compounds called ketone bodies. This is a perfectly normal state of affairs for the body. This is how it metabolizes fat. Lipolysis simply means fat burning. With sufficient intake of dietary protein, the body continues to be able to use glucose as fuel while optimally burning bodyfat.
However, in a fasting state, the body can enter ketosis-acidosis or ketoacidosis. Diabetic ketoacidosis (DKA) is a state of absolute or relative insulin deficiency, and in rare cases is fatal. Alcoholic ketoacidosis is along the same lines, but complicated by an episode of binge drinking (ethanol metabolism further reduces available glucose) combined with fasting. Non-diabetics who do not fast or regularly binge drink are not at risk.
You may see this used synonymously with ketogenic diets. However, I usually use this term to mean a diet which aims to reduce carbs, but not eliminate them. Ideally carbs are minimized and mostly from vegetables, with the occasional whole grain source like brown rice.
Opinions vary on this. Most sources consider low-fat to be around 25-30% of total caloric intake. Fat has 9 calories per gram, so if you eat 60 g of fat daily, that’s 540 calories worth, around 27% of our aforementioned 1950 calorie diet. The important thing here is that the fat is good fat. Check out the fat section. Some extreme sources, like the Ornish diet, aim for 10% fat, but this is in cases of major artery cloggage, and not applicable to most people (or even, recent research suggests, for heart disease patients). As an average person engaging in weight training, you’ll need some fat in your diet. I used to lurk in alt.diet.lowfat, and I knew it was time to leave when the folks there were trying to figure out how many fat grams were in their vitamin E capsules.
A diet that answers the question “What would Grokka the cave woman eat?” It includes meat, fish, poultry and eggs along with basically anything Grokka could kill and nosh. It includes fruits and vegetables — anything that can be plucked and eaten right away. It includes nuts and seeds. It does not include grains, legumes, or processed foods. There’s some debate about whether it should include milk, as many indigenous groups such as the Masai in Kenya or Sami in Finland do drink it.
In my opinion this one is a pretty darn good approach, as it’s arguably the way our bodies were designed to eat.