There can be multiple components to this: diet, lack of exercise, hormonal imbalance, stress, environmental toxins.
What you are eating matters. An excerpt from another recent article I posted that goes more in depth into how this matters:
If you eat a sandwich made with gluten-filled bread, nitrite-filled ham, cheese from a cow fed gmo corn and soy and filled with steroids, mayonnaise made with eggs from chickens who never get outside and are pumped with steroids to where they are growing so fast their legs can't hold them up...there are probably factors within the food you are eating that are promoting weight retention.
Now lets compare that to eating a chicken thigh from a free-range chicken, 1/2-1 sweet potato, and 1 cup of cooked Swiss chard. Do you see the difference?
Never forget to regularly exercise, 4-5 times per week. 30 minute walk, Zumba, Yoga that really works you, bike ride, skate, lift weights combined with cardio, run, jump on a trampoline, etc. This reduces inflammation and risk of blood blots, and increases metabolism, circulation, and energy.
Managing stress in healthy manner can allow your body to better manage insulin and other hormones, and reduce carb cravings and binges, thus promoting weight loss.
The air you breathe, the water you drink, the cosmetics and moisturizers applied to your skin, hair products, and make up all contain chemicals that are toxic to the body. I can help you to decrease your toxic load, which will help your hormones to become more balanced, and thus encourage weight loss.
And here's the big plus: everyone knows the importance of diet and exercise when it comes to weight, diabetes, and cardiovascular disease, but it is vital for reversing most illnesses and essential for maintaining and optimizing health - that is, prevention.