Factors affecting the proportion of body fat include genetics, level of energy balance, composition of diet, level of physical activity, environmental & societal influences, endocrinal factors, psychological factors, medication and smoking.
A person is more likely to develop obesity if one or both parents are obese. If both parents are of a normal weight only 7% of children will be obese. If one parent is obese, the incidence of obesity in children is 40% and it rises to 80% if both parents are obese. Genetics also affect hormones involved in fat regulation. Leptin is a hormone produced in fat cells which controls weight by signaling the brain to eat less when body fat stores are too high. If for some reason the body cannot produce enough leptin or leptin cannot signal the brain to eat less, this control is lost and obesity occurs. Lipo protein lipase (LPL) is an enzyme which promotes fat storage. Obese also have high LPL activity in their fat cells than lean people.
Dietary habits particularly the level of fat and energy intake is strongly associated with excess body weight. Excess dietary fat is readily stored in fat depots of the body. Excess carbohydrates can also be converted to fat. Overeating, irregular eating habits, nibbling in between meals, eating at night due to insomnia contribute to high energy intake and thus obesity. Alcohol intake provides empty calories and contributes to increase in central obesity. Consumption of fast foods that are high in fat and refined carbohydrates and low in fiber often used as regular additions to the diet also contribute to increased energy intake.
Level of physical activity
Increased mechanization, improved transport and working facilities reduce physical activity and promote sedentary lifestyle and weight gain.
Environmental and societal influences
Social pressures and official commitments of eating out and attending parties is a common cause of excessive intake of food and energy.
Certain genetic disorders as well as some hormonal problems such as hypothyroidism, insulin resistance, Cushing’s syndrome can cause weight gain. The female sex hormones also play a role, as obesity may occur after pregnancy, after removal of ovaries or uterus or at menopause.
There may be a physical connection between depression and obesity. For an individual who is lonely, discontented or depressed eating can be a solace. Obese people seem to be affected more by taste and appearance of food rather than hunger and satiety. Tension, anxiety, fear may further make a person resort to food for emotional satisfaction.
Drugs such as steriods, most oral hypoglycemics, anti-epileptics, non steroidal anti-inflammatory drugs, oral contraceptive pills and some antidepressants may also cause weight gain.
Smoking causes a marked increase in metabolic rate and tends to reduce food intake. Smokers frequently gain weight when they give up this habit.
Stress and weight gain
When faced with a stressful situation, our brain signals an acute immediate response causing the adrenal glands to release a hormone called cortisol and release of a chemical in the brain called neuropeptide Y, along with norepinephrine. When cortisol levels increase in response to stress, blood sugar levels rise as proteins are converted to glucose to serve as additional fuel. The unused glucose ends up being stored as fat once the stress is over, resulting in weight gain. Exposure to cortisol over long term can lead to weight gain, as your appetite and insulin levels are continuously increased. Neuropeptide Y is a powerful appetite-stimulating chemical which especially increases the desire for carbohydrate-rich foods. Yoga and other relaxation techniques are beneficial to combat stress. You need to become aware of situations that make you feel extra strain at home or at work and try to find ways to deal with this. Make sure that you have some time for yourself each day. You could gofor a walk, get a relaxation massage, do meditation or breathing exercises.
Did you know that people who get inadequte amounts of sleep are likely to gain weight?
With sleep deprivation, there is a reduction in metabolism and an increase in appetite. Inadequate sleep lowers levels of leptin, the hormone that causes you to feel full, while increasing levels of gherlin, the hormone that makes you feel hungry. Sleep deprivation also influences your food choices, making you crave high carbohydrate/high sugar foods. Sleep loss and stress decreases insulin sensitivity, putting the sleep deprived at higher risk for developing type II diabetes.
There are certain significant periods of life when an individual may be more vulnerable to the development of obesity. These are :
Status of maternal nutrition during pregnancy affects the development of size, shape & body composition of the fetus along with the metabolic competence to handle macro-nutrients. Close relationships exist between patterns of intra-uterine growth and the risk of abdominal fatness, obesity and their co-morbidities later in life.
Irregular meals, changed food habits, periods of inactivity alongwith physiological changes promote increased fat deposition especially in females.
If females excess weight gain may occur during pregnancy or following it.
Women tend to gain weight during this period due to reduced physical activity, declining muscle tone, increased caloric intake and other effects of aging. Postmenopausal women have reduced lipolysis, the process by which stored fat is released from fat cells.
Maternal nutrition during pregnancy is an important determinant of the birth weight of the infant. Epidemiological studies have indicated that the origin of major degenerative diseases such as diabetes and coronary heart disease in adults, which have not emerged as major public health problems in India accounting for considerable morbidity and mortality, may in fact be traced to intra-uterine growth retardation (IUGR) arising from poor maternal nutrition during pregnancy (Low birth weights : Significance and implication)
It becomes imperative to focus on the nutritional status of “Future Mother” at the prenatal stage than to make the future child face multiple health problems in later life. This can be a purposeful strategy to look forward to a more healthful nation by avoiding the unhealthy future human resource to some extent.
To give shape to this concept Un
Preventing obesity in children
Positive changes families can make to promote healthy eating & exercise habits and ideal weight in children.
Our body needs a regular, well balanced supply of nutrients to be healthy and fit. Proper nutrition in childhood can inculcate and lay the foundation for lifelong eating habits that contribute to the child’s overall well being and help them to grow up to their optimum potential without being overweight. By providing the child with a balanced diet as per the recommended dietary allowances for different age groups, we can give them a firm foundation for years to come and reduce the risk of nutrition-related diseases in the forthcoming years.
Parents should foster healthy eating and activity habits, be a good role model, offer a nutritious selection of food and involve children in making smart food and physical activity choices. Make the new health behavior easy for them by placing a bowl of washed fruit, such as grapes or apples, on the table which they can pick as snack when hungry. Create opportunities for your family to spend time together doing something active. Plan fun and active things for your family to do together, such as play in the park, walk through the zoo, tour some local sites, hike or swim.