The best way to lose weight has always been to switch to a better diet and make long term changes to eating and lifestyle.
The reason most people "yoyo" in weight is because they are miseducated about what "weight" actually is, the human body, how it works and the impact of changes to it.
In most cases, people in developed countries are overweight and dying of cancer more than people in less developed ones because of diet. There have been extensive studies linking processed/premade food to obesity and cancers. Switching to healthier alternatives, eating properly and cooking food yourself is a big investment. But it's the best one in increasing your life and reducing your weight you can make.
An average women needs consume around 1000 calories per day whereas a man around 1500. If an athlete or doing strenuous work then this count increases according to easily calculable factors.
Anyway, regarding the changes themselves you can make. You need to have the correct mentality as well as the "plan". You need to be draconian with yourself and be able to say "no" to certain foods - it's pretty similar to stopping smoking.
Pork and alcohol are both bad for the health and they also account for a lot of calories. You can reduce your calorie count by thousands a week by simply avoiding pork and reducing your alcohol consumption. This will aid you in losing weight and will give your body (and more sober mind too!) much more energy.
The other factor is eating less oily/sugary foods and more natural foods. Notice I'm not pushing you to this product or that product for the simple reason that none carry any scientific or medical weight (pun not intended).
Your not looking to lose 10 pounds by the end of the week. Instead your looking to gradually slim over a few months until your happy with your weight and then keeping it for the duration of your life.
Also, don't bother with exercises in gyms immediately - it's pointless and demotivating. Instead go for long walks whenever you can and avoid taking transport when the journey is short. You want to go to gyms and aerobics classes when your body is in a good enough condition to benefit from it.
A proper diet is more important than exercise when losing weight- think of it like cleaning a bin. If your still throwing garbage into it then even the best cleaners can't help you reduce the rubbish. You want your body to use more calories from your bodies reserves than from the food. Then gradually your looking to plateau so that your eating as much as your using.
So never be hungry, instead eat something with lower calories. My friend actually eats MORE to lose weight. But what he eats is tasty and almost calorie free.
Sorry if I come across bossy, as I'm more the "boot them into action" type rather than "hold hands and hope" type.