I have recently been reading a book “The Art and Science of Low Carbohydrate Living” by Dr. Jeff Volek (at time of writing an associate professor at the University of Connecticut) and Steve Phinney who is a physician-scientist with 35 years studying diet. Both the authors have an interest in promoting low carbohydrate diets for health and weight loss.
The book starts by explaining that for anyone conducting research into low carbohydrate diets the are “interesting times”. This is because of the numerous scientific publications published on carbohydrate restricted diets and an increasing number of clinical trials together with studies that look at the underlying molecular mechanisms. These studies which may explain why low carb diets can be so effective for weight loss.
The population of the USA together with other developed countries are currently experiencing an obesity epidemic. Scientists, policymakers and physicians all want to turn this around but no-one can agree the best way to achieve this.
The authors believe that moving away from the advice to eat a high carbohydrate diet to a low carbohydrate diet would improve the health and average weight of the general population.
Points made in this chapter.
1. Low fat diets have been promoted as healthy for the last 30+ years. During the same period obesity levels have skyrocketed.
2. High carb diets have the side effect of increasing blood insulin levels which is the fat storing hormone.
3. The consumption of saturated fat has been demonized in the media, medical textbooks and national policy. This is despite there being no connection between the intake of saturated fat and the long term risk of heart disease.
4. In fact the authors note that it is high carb consumption that increases blood levels of saturated fat.
5. The “one size fits all advice” to the whole population is misguided due to the metabolic diversity between humans.
Who is likely to benefits from reading this book? Anyone with an expanding waistline or those that have metabolic syndrome or diabetes.
Who won’t benefit from reading this book? Those lucky people, around 25% of the population, that appear to thrive on a low-fat diet.
Chapter 1 – Overview of Low Carbohydrate and Ketogenic Diets.
In this Chapter, the authors discuss the following points.
Why we are by evolution designed to eat a low carb, high fat moderate protein diet.
How the addition of large amounts of carbohydrate foods was only widely available after the adoption of agriculture around 8,000 years ago.
What is the definition of a “low carbohydrate” diet?
Definition of nutritional ketosis – explained in more depth in Chapter 7.
The difference between diabetic ketoacidosis and normal nutritional ketosis. How even health care professionals confuse the two states.
Chapter 2: Low Carbohydrate Lessons from Aboriginal Cultures
For millions of years, our ancestors had to survive on just meat and fat as their main source of dietary energy.
The exact diets of our ancestors is difficult to research, ancient peoples did not write anything down. Also when hunting cultures first came into contact with “modern man” a great deal of cultural information was either lost or wrongly misinterpreted.
There are a few observers of ancient hunting or herding cultures. For example, Vilhjalmur Stefasson who lived with the Inuit at the beginning of the 20th century.
All of these observers noticed that fat was considered the most important food. The Inuit for exmple would feed their dogs any lean meat from a seal kill and keep the fat and fatty organs for their own consumption. Examples of foods eaten are a fish called oolichan very rich in fat and pemmican a mixture of dried meat and fat that would last many months.
Although difficult to quantify exactly it appears that the Inuit had a diet of 15% protein and 80% fat as a percentage of calories eaten.
It appears to be a misconception that hunting and herding cultures had a high protein diet.
The types of fat eaten were dependent on the time of year the animal was killed permmican made from animals killed in the winter was rich in polyunsaturates and will spoil quickly compared to fat from autumn killed animals which is higher in saturated fats which will last through the winter.
Fish fat from eels salmon and oolichan was very highly prized. The fat from oolichan is very low in polyunsaturates and is primarily made from monounsaturated (similar to olive oil). This fat is less likely to go rancid so was highly prized.
Salt was a very important part of the diet of hunting and herding cultures. Blood was always a dependable source of salt although salt licks and springs were important.
If you eat a high carb then your need for salt is a lot lower compared to a low carb diet.
Chapter 3: The Modern History of Carbohydrate Restriction
Today eating a low carb diet will require you to do more than just avoid sugar and starches.