Despite of having a heavy meal, some people still do not feel full. 

Reason

Insulin hormone is secreted from the liver to change excess calories to fats. When fats in tissues increase, fat cells secrete leptin hormone to signal your brain that you don’t need to eat much, as the body already has excess calories in the form of body fats.

Leptin hormone is a hormone that makes you feel full and prevents excess energy intake. However, due to the food industry’s strategy and current consumer behaviors, this natural appetite control system becomes less effective. Constant intake of some foods such as sweets, snacks, beverages, dessert, sugary products plus others in a similar category, leads to accumulation of surplus energy. When that happens, large amounts of leptin are secreted but the brain does not effectively respond. This is because the foods mentioned above act as a stimulus for a person to eat more. This condition is called leptin resistance. It causes a person to continue eating even though he or she is not hunger. For example having more snacks after a heavy meal.

Carbohydrates and sugar

Carbohydrates is starch found in almost all kinds of plants, especially tuber crops and grains. Carbohydrates are composed of monosaccharides such as glucose and fructose, so that they can be absorbed into the body.

Glucose is sugar found in starchy foods and all kinds of carbohydrates, such as in products like rice and bread. Sucrose can be found in plants, such as sugarcane and coconut. Sucrose in snacks, beverages and foods comprises of two monosaccharides which are glucose and fructose. Therefore, in every sugar intake, your body gets an equal amount of glucose and fructose.

Fructose is found in ripe and sweet fruits. In general, fruits are composed of glucose, sucrose and fructose. Fructose is digested differently from glucose. Upon glucose intake, the body creates insulin to transfer glucose to body cells, including the brain cells which need glucose the most. However, fructose does not need insulin to absorb into the body. 

Almost all consumed fructose is digested in the liver. If the body adequately receives glucose, fructose is changed to triglyceride. Therefore, fructose is heavily associated with metabolic syndrome or diseases such as hyperlipidemia, hyperglycemia, low high-density lipoproteins (HDL), obesity and hypertension.

Research at Southern California University revealed the effects of two types of sugar. It found that fructose can better stimulate the reward area in the brain, when compared to glucose. In addition, fructose stimulates hunger and appetite better. An example is when a person skips a meal and has sweet fruits or juice instead to lose weight. They will in turn get hungry and crave for more food instead. Eventually, they may even gain more weight. In addition, sugar in soft drinks has higher fructose than glucose. Therefore, it best to avoid soft drinks as they can harm your health badly. 

Leptin hormone can greatly help control weight by signaling the brain when the optimal amount of food has been consumed. Therefore, we should avoid foods which brings harm to the health and impede leptin function. The body should get sugar in sufficient amounts only, as it can cause massive health issues in the long run.