Your feet, like all areas of your body, can store fat. Just as pregnancy can cause an increase in shoe size, changes in your body weight can affect the size of your feet. If your shoes begin to feel loose during weight loss, you can use different strategies to improve the fit of shoes you want to continue wearing.
Background
How much weight you'll lose in your feet -- and how that loss will affect your shoe size -- depends on how much weight you lose and, to some extent, your age. Body fat distribution varies between individuals and can change during your lifetime. Feet tend to become larger with age. Weight loss may cause you to lose half a shoe size or even more. Treating yourself to new shoes can be a part of creating your new image at your reduced weight.
Weight Loss
A combination of a healthy, calorie-restricted diet and vigorous exercise promotes weight loss. Your feet will become less prone to swelling as your body becomes more efficient from exercise and you reduce or eliminate foods that contribute to water retention, such as refined grains and high-sodium foods. Weight loss benefits your feet and all your joints. The many bones and ligaments of your feet won't have to support so much excess weight.
Slimming down also reduces the added impact of excess weight with every step you take.