Whenever you introduce any foreign object to footwear, it changes the way the shoe fits. An 1/8” over the counter insole added to a shoe will tighten it up quite a bit.
Shock absorption can be a help, but not if your shoe is tight. Your foot will more likely be comfortable if it can spread out and utilize the entire plantar surface. An internal shoe heel lifts on the other hand, are tapered from the heel to the area just proximal, or behind the metatarsal heads, (ball of the foot).
Therefore, internal heel lifts only obstruct the fit on the shoe around the heel collar. Your foot is not really falling in the heel seat like the shoe was designed for it to. An internal heel lift also transfers weight to the ball of the foot. The higher the lift the more pressure transferred. This can become a problem over time that the average person may not consider when trying to remedy foot, leg or existing issues.
Heel Lifts can also create ankle instability caused by the heel not sitting in the heel seat. Gel shoe lifts often do this too. It’s like standing on “Jello”, you have no stability. Heel Lifts that are more firm tend to work better in my opinion, but still can be unstable if not made correctly for each individual shoe. They are most effective when they cover the entirety of the heel seat.
I never recommend to my customer more than a 3/8” internal lift. I do have customers who have been using a 1/2” internal shoe lift in their shoes for years and they love it, but I will always err on the side of all lifts being external because the fit of the shoe is as or more important as the lift or elevation is, especially as we get older. Again, everyone is difference and if it’s not broken don’t fix it.
