The potential benefits to being on a high fat diet are:
- The ability to lose weight quickly.
- The ability to not eat for a long time and not feel hungry, and not lose physical or mental performance.
- The end of sugar cravings and binge eating.
- Having a greater amount of energy throughout the day for both physical and mental activities.
- Better sleep.
- The ability to perform in athletic events for a long time without hitting the "wall". The reason for this is that a person can store about 40,000 calories of fat, so it is unlikely that the person will run out of calories during any given athletic event.
- Reduced chance of getting cancer (cancer cells feed on glucose).
- Reduced chance of getting diabetes.
- Reduced chance of getting alzheimer and dementia.
- Reduced chance of getting a heart attack or stroke.
The high fat diet has the following principles:
1. Avoid carbohydrates, especially empty carbs and sugar. This means to avoid pasta, wheat, bread, corn, rice, soft drinks, fruit drinks and sugar.
2. Eat foods which contain large amounts of fat (including saturated fat), and protein. This includes meat, fish, milk, cheese, butter, lard, eggs and nuts.
It is important to understand the biological process that causes us to get fat. The following summary comes from Gary Taubes book: Why We Get Fat. Most people believe we get fat because we eat more calories than we work off (by exercise and physical activity). This is incorrect. The reason we get fat is because of a hormone called insulin which is created when we eat carbs. Insulin tells the cells in the body that they need to absorb glucose (sugar) that is entering the body because glucose is actually poisonous in the bloodstream. Insulin also tells the body to stop burning fat for energy in order to use up the incoming glucose. Insulin accomplishes these two tasks using two enzymes: Lipoprotein Lipase (LPL) and Hormone-Sensitive Lipase (HSL). LPL tells the cells to accept glucose. So the more LPL on your cells, the fatter you will become. HSL tells the cells to release fat. So the more HSL on your cells, the thinner you will become. High levels of insulin increases LPL and decreases HSL, which is necessary in order to remove glucose from the bloodstream where it is toxic.
Not everybody who eats carbs is fat however and this can be explained by how different people utilize LPL in their bodies. Some people have higher LPL levels on their muscles which mean that the muscles will absorb the glucose and burn them for energy. These people will have higher energy levels. Other people have higher LPL levels on their fat cells. The fat cells don't utilize the glucose like muscle cells, they just store the fat and get bigger. These people will have lower energy levels, and become fat. The following factors play a role in whether muscle cells or fat cells will have higher LPL levels:
1. Genetics. Some people have genes which cause them to have higher LPL levels on muscles.
2. Eating fructose. Fructose will change your LPL so that the muscles will absorb less glucose, and your fat cells will absorb more. This explains why countries that eat a lot of carbs, but low fructose (China and Japan eat a great deal of rice, but relatively little sweets) have less of a weight problem.
3. Aging. As people age, LPL levels decrease on muscle cells and increase on fat cells. One reason for this is caused by a decrease in estrogen and testosterone.
By switching to a high fat diet however, all of these factors will be mitigated because you will have low insulin levels and you will not be consuming glucose. Your body will switch to using fat which is converted into ketones for energy.
Eating carbs year after year produces a negative feedback loop where people end up becoming excessively fat and possibly diabetic. As you eat carbs, your insulin level rises. If your insulin level is constantly high, your cells start to become resistant to insulin. This is because glucose is toxic not just in the bloodstream, but also in your cells as well. This means that in order to force the cells to accept glucose, the body needs to produce even more insulin. This insulin will create higher LPL levels and lower HSL levels which results int less fat being used for energy. Eventually, the pancreas will not be able to produce enough insulin and you will become a type 2 diabetic. In this case, your blood sugar level will be too high and you will need to take actions to lower your blood sugar level.
The high LPL levels on fat cells act in a way that is damaging to the person as a whole. Even if the muscles need energy, or the brain needs energy, the LPL on the fat cells will be satisfied first. That means people need to eat ever more carbs because they have to satisfy their fat cells first, and then eat enough afterwards to satisfy their muscles and brain. When people go on a high carb/low fat diet with a lot of exericse, they will starve their muscles and brain which leaves them feeling lethargic and stupid. This is why most low fat diets fail. Eventually the body will begin consuming itself in order to find energy including muscles, bones and even the heart.
There is a special form of low carb diet called the keto diet. Keto is short for ketosis which is body state where the digestive system is optimized to burn fat instead of carbs as the main source of energy. By default, when a person consumes both carbs and fat, the body will consume the carbs first, and the fat later. A typical body stores a maximum of 2,000 calories of carbs. When this is consumed, a person will hit a "wall" and find physical exercise (as well as thinking) to be more difficult. This is because the body is out of carbs to consume and a person in a non-ketosis state is optimized to have their muscles and brain consume carbs. If a person keeps their intake of carbs to approximate 50 grams or less a day, the body will slowly adjust to burn fat instead of carbs. What happens is that the liver will begin consuming fat and produce ketone bodies which are consumed by both muscles and the brain. Depending on how large your intake of carbs is, it takes between 2 -4 weeks to make this adjustment. During this adjustment period, a person typically feels poor and lacks energy because the body is demanding carbs for energy, but it is not being delivered, and the person has not yet adjusted to burning fat optimally. This requires a very strict diet. If a person decides to eat a lot of carbs for a day, the body will revert back to burning carbs and returning to ketosis will take some time again.
The idea that is generally accepted is that saturated fat is bad for you. This is related to the second idea which is that cholesterol is bad for you. First, it is believed that saturated fat is harder to digest and more likely to make you fat. Also, saturated fat is more likely to clog your arteries and give you a heart attack. The truth is that saturated fat in animal meat and butter contain a great deal of vitamins including K2, A and D. Heart attacks are not caused by fats or cholesterol clogging up arteries, but rather due to inflammation of the arteries. The cholesterol is actually used by the body to heal the arteries. Thus, reducing cholesterol makes it more difficult for the body to heal the arteries, and makes it more likely for somebody to suffer a heart attack. Below are the items that can cause inflammation of the arteries (Link to Source):
- Oxidized cholesterol (cholesterol that has gone rancid, such as that from overcooked, scrambled eggs)
- Eating lots of sugar and grains
- Eating foods cooked at high temperatures
- Eating trans fats
- A sedentary lifestyle
- Emotional stress
There is empirical evidence that saturated fat is good for you. The Inuit eat mainly saturated fat from whale meat, and do not have a higher incidence of heart attacks. My readings have recommended 20% polyunsaturated fat, 30% saturated fat, and 50% monounsaturated fat.
Then we move on to the belief that whole grains are good for you. One argument for whole grains is that they contain fiber. It is true that they contain fiber, but so do many fruits and vegetables which the high fat diet also encourages people to eat. Another argument is that grains contain vitamins. But there are far more vitamins in food encouraged by the high fat diet such as meat and vegetables. The problem with whole grains is that they are mostly empty carbs. Unless one gets a lot of exercise during the day, these carbs will turn into fat. Excess carbs can also increase the chance of diabetes. People's nutritional demands will not be met by carbs, so their bodies will soon be hungry again, with the result that people on a carb based diet are more likely to eat more total calories than people on a high fat based diet. A vegetarian diet can be good for you so long as empty carbs are not a large part of your calorie intake, but many vegetarian diets encourage eating empty carbs such as whole wheat and brown rice. Also, vegetarians often have problem maintaining their muscle mass due to inadequate protein intake.
Also, I would like to make a comment concerning exercise. Exercise does not make you thin. Exercise can change your muscle to fat ratio, but it will not change the underlying levels of LPL and HSL which are what cause you to get fat. When exercising your body will direct glucose to your muscles rather than your fat cells, but when you stop exercising, your body will reverse this and direct glucose back to your fat cells. There is no permanent change.
Doing long amounts of jogging or similar aerobic exercise can do more harm than good - it is possible to burn your muscles. It is better to do the kinds of exercises which build muscle mass such as weight lifting. Also, if you are going to run, it is better to do intervals of very fast running, separated by walking. Such as 30 seconds of sprinting, following by a minute and a half of walking, and doing this for 20 minutes. This will build your muscles rather than burn them and it can be applied to cycling, the elliptical machine, or other aerobic exercises. If you look at the physiques of short distance sprinters and compare them to the physiques of marathon runners, you will see the difference in results between these two forms of exercise.
Another idea I hear about concerning exercise is that once fat is replaced by muscle, the muscle will burn more calories even at rest, which makes it easier to maintain your weight. While this is true, the actual increase in calories burned is insignificant. If you are able to transform 5 pounds of fat into muscle, this would only burn an extra 20 calories per day which is very small (Gary Taubes). Even if the additional muscle did burn more calories, this would not stop the insulin process and the LPL demands from the fat cells mentioned above.
The general idea behind the high fat diet is to eat food that our ancestors ate for the past tens of thousands of years. Our digestive systems evolved over this time to work best with certain kinds of food. Recently (in the past 4 or 5 thousand years) new foods have been introduced through agriculture which the human digestive system has not evolved to process well. These includes grains, wheat, corn, sugar, soy and other carbohydrates. When people eat the kinds of food the body processes well, then they are more likely to be fit, energetic, thin, muscular, and disease free. When the new foods dominate the diet, then people are more likely to become overweight and fall victim to diseases.
There is strong evidence to support the high fat diet. There are 18 case studies which show that a low carb/high fat diet are more effective at reducing weight than a lot fat diet/high carb diet. There are studies which show that a high fat diet causes heart attacks, but these studies are all survey studies which are not as effective as case studies. Furthermore, the survey studies does not separate organic fat from processed food which often contains carbs as well as fat. The high fat diet encourages only eating organic food.
I want to stress that the high fat/low carb diet is not a temporary diet like low fat diets which reduce your calories consumes. If you want the benefits of the high fat diet listed above, then you have to make this diet a permanent change.