No you are not ruining anything. Your body will see the glucose increase from the juice and vinegar, convert it to glycogen if you are sendentary or actively use the glucose if you are active and then you will go back to lowering liver glycogen until “Metabolic Switching” occurs. This is the process where you then start converting fat into ketones for energy. Your drink will not significantly impact this process, as you’ve described it.
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Your energy management systems are continuous processes always adapting to what you are doing. As you eat and drink your body will look for protein and carbohydrates to convert into glucose, as glucose is prioritized for to fuel the body. Fat is a secondary energy source and eating fat doesn’t add to glycogen but instead gets stored directly as fat. It is also important to keep in mind that a calorie is a unit of heat that is produced by the burning of glucose. That same unit of heat can be produced by the burning of fat, but only if long term storage of glucose (glycogen) is low enough in the liver. So calories do not add up, but glycogen and fat does. This is how all fat loss works, CICO does it through limiting energy rich foods, Keto does it through limiting foods that refuel glycogen stores, IF does it through limiting eating windows.
I hope this helps!
It will not ruin your OMAD and it will probably not slow down weight loss, but anything with flavor, even with no calories, will keep you from getting into autophagy if you care about that at all, many don’t unless they have a lot of extra skin. I generally just stick with plain water and black coffee while fasting and it keeps me from feeling hungry.