Pat Lyons and I wrote the book, Great Shape: The First Fitness Guide for Women in 1988.  Since then, the interest in the topic and the resources available to large women have grown exponentially. 

Large women are not morally obligated to exercise. Rather, we should have the right to pleasurable and safe physical activity. Joyful play and feeling competent in your own skin help you feel safe and healthy, combat stress and depression, and resolve many common physical problems.

Many barriers still exist when large women try to become more active.  They include

• less accessible clothing (although thankfully this is changing),
• activities paced for lighter bodies,
• possible public ridicule or hostility,
• a lack of safe public spaces (especially in the evening when many women who work during the day could exercise),
• lack of time,
• lack of money,
• lack of motivation to spend time on oneself,
• the diet-and-exercise mentality many of us are still haunted by, 
• the diet-and-exercise mentality of other people exercising around us,
• nasty memories of PE
• the possibility that we don't have movement skills because we have spent our lives avoiding it.

Moreover, when our exercise schedule gets disrupted (as it does with everyone) because of deadlines, sick kids, injury, illness, etc., it can be harder to get back into the groove because 

• we are moving more weight and so it feels harder to move after being sedentary,
• we are vulnerable to feeling like our inactive selves are our "real" selves because of the "fat and lazy" stereotype,
• we are vulnerable to feeling that this disruption means we must lack will-power because of the "fat and out of control" stereotype,
• if what got in the way of your exercise schedule was another person's need for you, you might feel it is being selfish to exercise.

A BodyPositive approach has the goal of integrating movement into your life for the rest of your life.  If you look at it as a very long-term process, in which you never "arrive," you begin to care about how it feels day-to-day, and how to develop the skills to keep coming back.  It is more like learning a foreign language: 

• At first it seems pretty difficult and there's more effort and self-consciousness, but there still can be fun aspects to it.  
• It takes a long time and a lot more effort than our quick-fix culture prepares you for.
• Later when you've wrestled with it for awhile, you begin to notice more effortless moments. 
• If you get out of practice, you can feel overwhelmed at the thought of coming back, but once you do it, you are surprised at how much comes back easily.
• When you've become fluent you can hardly imagine your life without it.

A long-term approach means you have to pay attention to

• your body's hunger to move (get in touch with it! Give it a name! Write a haiku about it!) 
• what you find pleasurable about movement (being with other people? being alone? moving to music? to quiet? in water? on land? vigorously? gently?)
• the blossoming athletic identity within you ("when it's not raining, she's gonna be outside, that's just how she is").