People don't put on weight because they tend to binge on main meals, but because they eat when not really feeling hungry. Whenever hanging out with friends, most of the people order a beverage, such as juices, or desserts now and then, and do not really take that as a calorie intake, so they end up getting fatter.
There is a trick that can help you avoid consuming more calories - just drink water. If feeling hungry, just drink a glass of water as it will take the edge off of hunger. You can do at night or when/if waking up in the wee hours of the morning and feel the urge to grab something to eat.
Eat during the day at the same time so that to have your body produce stomach juices at exactly the same hours, which will boost the digestion.
If, however, you fail at fighting off the hunger, just go for an apple or some other low-calorie food, which will satiate your cravings. Such foods are milk, white cheese, sunflower seeds and others.
What type of water do you drink?
There are five options you have: tap (I do not recommend it), mineral, spring, mountain or distilled water. It is recommended that you either prefer mountain water or rotate it with mineral or distilled one. Be careful when it comes to the mineral water since it contains a certain amounts of chemical elements. The human body needs about 1,5 L of mineral water on a daily basis, however the intake of such may give rise to former health issues or trigger new ones; not to mention that it takes a major toll on the heart.
Never drink an iced water since it hinders the digestion. This is due to the ferments, assimilating the food, which can function properly at about 37 C , so when drinking iced beverages, this environment gets affected.