The biggest puzzle these days is how to lose weight and how to not regain the lost weight. Thus maintaining an ideal weight is the most challenging thing. Since there are so many different ways that people keep trying, it is imperative that we understand the science behind it. That way we can judge and apply healthy ways of losing weight. Also if we understand the scientific concept behind it, the lost weight will stay off and we will not have to struggle every day to keep it that way.
Body systems that control our appetite not only control food choices and intake quantity for the short term but also our weight in the long term. It does that by sensing the total amount of fat or adipose tissue which is stored in our body.
Physiology Behind Weight Loss
Every individual is different when it comes to weight loss or weight gain, hunger, and genes. However, the biological processes in every human being are more or less the same. The biological process involves various hormones which our guts secrete into the stomach into the blood in order to tell the brain when to eat and when to stop.
The stomach secretes Ghrelin when it needs more calories. Following it with the food eating, the brain waits for the signal as to when to stop. Here guts release leptin, another hormone that gives a sense of fullness and satiety. Our ‘Metabolic Brain’ receives these signals. Now, these are the hormones that are similar in all human beings. Still, there are few people who keep gaining weight whereas others who do not. Hence the process is further complicated by our brain. The ‘cognitive and emotional brain’ takes signals from the body’s sensory organs about the smell, stress levels, looks of food, etc. Hypothalamus now combines information from both sections and decides what to eat and how much to eat. The however cognitive and emotional brain can override the metabolic brain signals overriding the feeling of fullness.
There are various factors that influence eating behavior. A few of them are as below:-
- Amount of hungriness, feeling the need of appetite, and taste to achieve satiety.
- Economic condition determines the quantity and quality of food we can buy to eat.
- Accessibility of food.
- Time and skill are available to cook and eat.
- Social culture or regional preferences of food.
- Meal patterns of family and peers at work or school.
- Stress, mood, or guilt.
- Attitude towards own fitness.
- Knowledge of food and associated risks/benefits.
- Age, profession, work environment of a person.
Besides the genetic layout of a person, there are many factors that may influence the eating behavior of a person. There is no ‘Single Solution’ to the problem or weight loss and keeping lost weight off. We will have to combine biological, physiological, and environmental processes to make individual solutions. It is quite evident from above that just eating fewer calories than consumption may not be enough to keep the weight off. Even people doing untargeted exercise are unable to keep the weight off. As soon as they leave diet control or exercise for even a short period, the weight comes back to, where it started.
To understand it better, we need to first understand the meaning of ‘Set Point’. The body has an understanding of the amount of weight and fat it needs to store in reserve in order to survive for as long as possible in case no food is available or starvation happens. This point is the ‘Set Point’.
Every individual is different when it comes to the setting of the ‘set point’. However set point in every individual is also not fixed but can vary depending on various environmental factors as mentioned above. Hence if our set point is higher and we lose fats below setpoint, the body does everything it can to store reserves back to setpoint requirements. It can slow down metabolism, increase appetite by sending signals of hungriness and even delay the signal of sense of fullness. Hence an individual regains fats lost and weight.
The Genes Behind Weight Loss
It is important to discuss Genes as they may not be the only factor but one of the important factors in determining weight and obesity.
There are few who have the FTO gene commonly known as the fat gene. This reduces the production of leptin and hence makes an individual eat more than required. This gene contributes in a big way towards weight gain and obesity.
A gene known as GHRL encodes for ghrelin production. This gene is associated with higher BMI and leads to less insulin secretion when we eat glucose.
Genes also influence taste. Some people have craving for sweet food and others have other kinds of food. The taste gene influences to the extent that even if they are full, or given or shown food of their choice, they feel like eating more and hence resort to overeating. This leads to weight gain and obesity.
Science is yet to answer any questions on how to solve the problem of being overweight and obese. However few things clearly emerge from the above. We need to understand various factors and biological processes involved. We will have to adjust to our behavior in order to correct anomalies in our genes. We can achieve this with the motivation to maintain an ideal weight. Besides this, it is important to reset our ‘Set point’. This will draw our system out of the adjustment and make our lost weight sustainable. As of now, we can only achieve this by exercise (both aerobic and weight training) as we need to increase our muscle mass especially (Type I muscle fibers). This way we can increase our rest metabolic rate or in simple words, our body consumes more calories even when doing nothing. Diet changes should be more realistic and something which can be made permanent. So in fact I will call it lifestyle changes rather than diet changes.