From my understanding, cellulite appears when there is a break down or wasting of the webbing that surrounds the fat cells, which is made of proteins such as collagen and elastin (looks like chicken wire). This makes the fat cells more obvious in appearance. It can be caused by poor diet and/or inactivity, and genetic factors.
Over the years, I have been able to reduce the appearance of cellulite in many female clients by restoring the muscle mass to the butt and thighs. I have also done this on myself, as my legs once upon a time looked like cottage cheese.
Have you ever wondered why even the skinniest of people still have cellulite? It is not just associated with the overweight, but more commonly with people who do not exercise and sit a lot, which leads me to my next point- fluid retention, which Christine, Jocelyn and Ariadne have already mentioned in their references to staying well hydrated and reducing salt intake.
Make sure what you are seeing on your clients isn’t simply excess fluid sitting in the cells of the hips and thighs, as this can be sorted out almost straight away.
If the lady doesn’t move much or has poor diet and water intake below requirements (think typical office worker), then fluid can pool in the lower half and give skin the “rippled” appearance.
Exercises like squats and hip extensions work wonders for both reducing both cellulite and fluid retention. You could encourage your ladies to get out of their chairs once every hour or so and perform body weight squats or any other appropriate glute exercise for them as individuals, to get the fluid moving through the lymphatics. Following this activity you may find it appropriate to suggest 200ml of water before sitting back down to work again.
Also make sure her glutes are actually engaged in exercises like squats and lunges. I haven’t looked at your profile so I do not know your experience level or if this is appropriate for me to say, but a lot of trainers miss identifying this, and the client gets over developed quads and under developed butt and upper hamstrings, regardless of fitness level and ability.
Another thing to consider is body composition- if a particular lady has an exceptionally large amount of body fat on the hips and thighs, but a comparatively smaller upper body (think the lady who complains dresses never fit as she is 2-3 sizes larger on the bottom, not just your normal “pear” shape), she may have a hormonal imbalance contributing to both the fat accumulation and the fluid retention.
I hope this information is helpful.