Our metabolism is influenced by many factors.  One of the key factors controlling our metabolism is the amount of lean body weight (muscle) we carry.  The more lean muscle we have the higher our metabolism and the more energy our body burns.  This means that when there is more lean muscle mass the body does not store so much energy in the form of fat and a person is less inclined to pick up weight. 

With aging we start to loose lean muscle mass and therefore the metabolism slows down.  Mmasebidi this means that 13 years ago you were younger and had more lean muscle.  It would have been easier to maintain your weight back then but now that you are older your muscle mass has decreased and by still eating the same amounts your body will store the excess energy. This means that the older we get the easier it will be to put on fat weight and the more difficult it becomes to loose excess weight.

The reason your husband picked up less weight than you even though he has more of a sweet tooth may be that he is more active than you.  When we are more active we use more energy than what we would if we were following a sedentary lifestyle.  By using the energy that we take in from our food there is less chance for our bodies to store extra energy in the form of fat.  So yes; a person doing field work is less likely to pile on the kilos than someone sitting in an office.  Exercise increases lean body mass, which in turn increases metabolism.

Another reason for your husband’s smaller gain in weight might also for the male hormone, testosterone.  Men have more testosterone and usually more muscle as well.  Testosterone plays a part in the metabolism by promoting protein synthesis.  Testosterone is anabolic, meaning it builds up bone and muscle mass.  The more muscle they have the higher their metabolism and the higher the energy ingested (through food and drink) before weight gain is experienced.

Oestrogen is the female hormone and helps to lay down fat as storage especially on the hips and thighs, creating a more curvaceous shape. It also promotes the development of female secondary sexual characteristics, such as breasts.  Oestrogen is also involved in regulating the menstrual cycle and may increase vascular permeability, and cause edema.

Another factor that influences our metabolism is the amount of water we drink every day.   At least 6 to 8 glasses per day is necessary to remove waste products from the body.  The lower the load of waste products in the body, the easier it is to burn energy effectively.  

Eating small meals at regular intervals also helps to increase the metabolism.  By eating regularly it means that the body is never starved, and so a person is less inclined to overeat because blood sugar levels stay more stable and the body does not have to “store” food for times when food are scarce.