One of the tools I have been using to decide if my meals are ketogenic is to calculate my Ketogenic Ratio. That is the ratio of foods that raise ketones vs the foods that lower ketones, i.e. produce glucose.
Ketogenic Ratio (KR) = (Fat * .9 + Protein * .46) / (Carb * 1 + Protein * .58 + Fat * .1)
|< 1.0||Not ketogenic, if healthy you won’t register ketones|
|1.0 - 1.5||Mildly ketogenic, you may register ketones at this level|
|1.5 - 2.0||Ketogenic, most people will register ketones|
|> 2.0||Very ketogenic, you should definitely see ketones in this range|
But one question that immediately came to mind was “How does weight loss affect my ketogenic ratio?”
The formula only takes into account macronutrients consumed, not macronutrients used. When losing weight, you will be burning body fat in addition to dietary fat. Lucas Tafur discusses an alternate formula for Total Ketogenic Ratio (TKR) which attempts to include body fat as well. I’m not convinced of its accuracy however especially when it’s not possible to accurately measure total caloric expenditure outside of a lab. I know what my body theoretically burns each day and also know that it rarely performs as expected!
While The Art and Science of Low Carbohydrate Living doesn’t address the ketogenic ratio, they do provide some guidance. When looking at percent calories, they point out that when losing weight your % protein will appear too high (> 30%) but when you take into account weight loss, it is actually much lower (< 25%).
My interpretation is that you calculate the calories you are eating and compare that to how much you theoretically burn. The difference should be included in the fat category when calculating your ratio. For example, say you are at a 180 calorie deficit, 180 cal / 9 cal/g = 20g fat. I would add 20g to the Fat variable in the formula and then calculate my ratio.
In practice I am going to attempt to identify (using my ketone meter) how much carbohydrate and protein I can eat without restricting calories to generate adequate ketones. Then I will cut back on dietary fat to generate a mild calorie deficit, until either my ketones drop too low or I become hungry or tired. Then I’ll add back until I find a happy medium of satiety, energy and weight loss. Sounds simple, eh? :)
I think the ratio is interesting, and since my nutrition software calculates it for me, it’s an easy way to gauge how close I am to my goals. However, in the context of weight loss, it becomes difficult to calculate and maybe not as relevant. My take is that as long as you are making ketones and are at a slight calorie deficit (it doesn’t have to be 500 cal / day) you will eventually lose weight**.
** With the usual disclaimer that if you have other unaddressed hormonal imbalances, even if you do all this right, you may not still lose weight.