The Science Behind the Ketogenic Diet
Our bodies run on two primary fuels: glucose and fatty acids.
It's kind of like we have a car with an engine that can run on either gasoline or diesel. We fuel up by eating food. If we eat food containing sugars and starches (carbohydrates) we convert those quickly into glucose and we run as glucose burners. All the cells in our bodies can turn this glucose into energy. This is why it's sometimes called our primary fuel. If we eat more glucose than we need for immediate exercise requirements, our livers sweep up the extra glucose and turn it into saturated fat, and sends this (and any fat we have eaten) off to our fat cells to be stored for lean times.
If we don't eat any carbs and instead eat fat (and moderate protein) most of our cells can easily burn the fatty acids for energy. It could be the fat in our food but it could also be fat that we have stored in case food is ever scarce. This state is called nutritional ketosis. We often go into ketosis during sleep (if we haven't eaten a late dinner), and of course anyone doing a fast is running their fat burning engine.
Some cells in the body (and the most metabolically active organ - the brain) can't burn fatty acids, but your brain can use ketones. These are small water soluble molecules that you make as a by product of metabolising fats.
Luckily your liver makes glucose even when you don't eat any carbohydrates, and by a quirk of fate, when it is making glucose for your brain it is also pumping out a lot of ketones.
We evolved to be predominantly fat burners for 11 months of the year. At the end of summer (when ripe fruit is available) we became predominantly glucose burners. We are good at adapting from one mode to the next, although it can take a few weeks for the machinery of fat burning to spin up to full efficiency and put our glucose burning into idle. Once you are adapted to burning fat (keto-adaptation) and you start eating carbohydrates again, in a few weeks your glucose burning metabolism will be back up at full speed.
In our modern world, however, we are burning glucose all year round, 6 meals a day. Our bodies have forgotten how to burn fat. We just store it and never get a chance to burn it. Some of us have become so metabolically deranged working our glucose metabolism 24/7 365 days a year that our mechanism for safely metabolising glucose has become broken - and that is how we got type 2 diabetes.
The Ketogenic diet addresses this by forcing your metabolism to predominantly burn fat, restricting your dietary carbohydrates, and relying on your liver to make all the glucose and ketones your brain needs. Most of the rest of your body burns fatty acids directly for energy.
When you give your body fat, it becomes good at burning fat! When you give your body glucose, it becomes good at storing fat!
But what about the studies that show correlation between fat intake and heart disease? If you look carefully, study after study shows that increasing fat intake while eating more than 50 grams of carbohydrates a day will indeed increase heart disease and all that goes with it. These studies fail to remove the carbohydrates!
Some people are good at switching from one mode to the next. Type 2 diabetics, however, have a broken metabolism for dealing with glucose, so when we eat carbohydrates we get progressively worse glucose control and consequently get sicker over decades. We can, however, hack our body into being full time fat burners. This hack not only allows us to maintain safe glucose levels (http://www.ncbi.nlm.nih.gov/pubmed/19099589), with less medication (http://www.ncbi.nlm.nih.gov/pubmed/25071075), but improves many of our biomarkers of disease.
If we additionally choose to use this hack to also lose weight it preserves more of our our resting energy expenditure (http://jama.jamanetwork.com/article.aspx?articleid=1199154) and over time if we have intervened early enough can allow us to reverse the progression of type 2 diabetes (http://www.yorku.ca/mriddell/documents/istype2reversible.pdf).
This dietary strategy is still something that Diabetes Associations around the world are only just now looking at, and Dietetic associations are firmly opposed to, as it is not a modest tweak of their established food pyramid, but a complete upending of it. There are political issues as well. The USDA has a conflict of interest when it comes to dietary guidelines. when it comes to dietary guidelines. That said, the ketogenic diet is quickly becoming the first approach in diabetes management among progressive medical specialists http://www.nutritionjrnl.com/article/S0899-9007(14)00332-3/pdf).
The bottom line for us is that following the low fat model for the past 40 years has made us fatter and sicker. In 2012 some 52% of US adults - according to the projections in this study (http://jama.jamanetwork.com/article.aspx?articleid=2434682) - were either diagnosed with type 2 diabetes (9.1%), or undiagnosed type 2 diabetics (5.2%), or they had a condition called prediabetes, meaning they were metabolically deranged but not quite at diabetic levels (38%). So, it is no longer just some of us. Most of us are in trouble.
That is why we're 2 keto dudes, and why we're doing this podcast.