If you are wanting to make a sacrifice on Fridays and food doesn’t work switch it to something else.
I heard Fr. Larry Richards discuss this on a radio program one day regarding meat consumption.
I run as a hobby, for my health and for stress relief. To keep my weight, cholesterol, triglycerides, blood pressure down I already watch how much red meat, sugar, alcohol and fat I consume. There are many others who do the same. Does calorie restriction or not eating red meat on Friday mean anything if it you already do it for some other reason?
If you don’t have much control over your meals, I think it’s okay substitute some other sacrifice.