The theory
Keto is a low carb, moderate protein, high fat diet.
It gets its name from the mechanism it relies on for energy. There are three sources of energy for the body:
- Carbohydrate: turned into glucose.
- Protein: also be turned into glucose.
- Fat: turned into ketones, in a process called ketosis.
If you eat a very low carb diet, and make sure your protein isn't excessive, your body has to burn fat for energy. When you're doing this, you're 'in ketosis'.
Getting into ketosis takes time. Your body usually has about 24hrs of glycogen stored, which can be released and turned back into glucose. So on the first day of eating a keto diet, you're still actually running on glucose.
After the glycogen stores are gone, your body has to start burning fat to produce ketones. It can take time to adapt to this: especially for the first few days you may experience keto flu (symptoms include headaches, lethargy, brain fog, irritability, and just generally feeling off). However, many of the symptoms of keto flu can be reduced or avoided by making sure you get enough electrolytes. Read more in r/keto | adapting to a low carb lifestyle. Note that it can take weeks to fully adapt.
Potential benefits of keto
There are many benefits claimed for keto, including:
- Blood sugar control: inevitably, if you're eating very little carb, you're unlikely to have high blood glucose.
- Weight loss: the diet is filling, and it forces your body to fully adapt to burning fat, making it easier to maintain a calorie deficit. But do note the calorie deficit: keto isn't magic, if you eat more calories than you burn, you will still gain weight.
- Avoiding energy crashes: you steadily burn fat as needed, avoiding blood sugar spikes, and the subsequent crash.
- It is used to treat some conditions. It was originally developed to treat epilepsy. However, medical/therapeutic keto is a little different from the looser version practiced by most people. I won't cover it here: it's not the program I'm on, or something I've researched.
And some more subjective ones:
- Some people experience increased energy, and/or better mental clarity.
- There are experiments ongoing using keto to tackle a range of mental health problems.
- Some people seem to find it effective as a way to control binge eating.
As with any diet, exercise caution: if you look hard enough, you'll find someone claiming keto cured any condition you care to name.
Why keto for type 2 diabetes?
As mentioned above, keto has (at least) two benefits for type 2 diabetics:
- Improved blood sugar control.
- Weight loss: losing weight improves insulin resistance, and may even put your diabetes into remission. For details on the mechanisms behind weight and type 2 diabetes, I strongly recommend Life Without Diabetes: The definitive guide to understanding and reversing your type 2 diabetes by Prof. Roy Taylor.
Virta Health | Reversing Type 2 Diabetes is a good, short, simple guide on this topic.