The Science behind fat loss: why isn’t everyone fat?

It’s that time of the year when everyone is fully energized and motivated to make an action plan of their wish lists and new year resolutions. You go over the list and find this one wish that has been in your list since forever. You feel as if your heart is sinking into the stomach. Yes I’m talking about weight loss/fitness goals.

Weight loss is that daunting task which most people struggle with. Initially everyone is determined to head to the gym or do the at-home workout sessions, but as time passes we lose our hopes if we don’t reach up to our expectations. This happens as a result of making some unknowing mistakes during the process:

Mistake #1 is keeping high expectations, for e.g. “I will lose 5 kg of my weight in this week. Now this is not impossible but to achieve it you will have to starve all day plus do some hard core workout daily. This is no less than a nightmare for beginners. Thus, we should keep targets that aren’t number-oriented. Keep goals like trying to workout, eating healthier and avoiding high calorie junk food , meditating for 10 minutes, etc and doing these things repeatedly day in and day out.

Mistake #2 is not trusting the process. We usually think that once we start a fitness regime it will give us results everyday, but that’s not true. Fat loss happens as a result of consistent workout, mindful and healthy eating in an unhurried environment. So just trust the process and trust yourself so that you stay motivated all along.

Causes of fat gain:

1.Easy access to food. These days food is available at all the corners of the world, you don’t need to hunt for it. To make things even easier, food can be home-delivered for your own convenience.

2.Addiction to junk food or foods that are high in calories, leading to overeating. Even processed foods lead to fat gain

3. Bad eating habits like skipping breakfast and having a super heavy lunch. This also leads to over food intake and more acid production in the stomach leading to gastric problems.

4. Our lifestyle also decides how we are shaped, in the sense, oversleeping, inactivity, no exercise, sitting in front of tv/laptop all day, high stress levels, etc makes us lazy and triggers weight gain.

5.Eating too much sugar or sweet foods

6. Sleep deprivation is one of the major factors of weight gain.7–8 hours of sleep is considered to ideal. Even too much sleep like 10–12 hours can accelerate weight gain.

7. Genetics. According to a Scientist Dr Stephen O’Rahilly, obesity is surprisingly not only because of mutation of genes pertaining to metabolism (breakdown of foods to get energy), but it can be because of failure in satiety (feeling of fullness) signals in the brain leading to people eating too much.

8. Hormonal issues. Less production of thyroid hormones in the body leads to low metabolism which in turn makes us fat.

9. Underlying health problems like diabetes, PCOS, fluid retention, etc

Consequences of weight gain

  • Invites heart diseases such as a stroke, coronary heart disease, artery blockage due to high amount of cholesterol, high blood pressure(hypertension)
  • Increased risk of pre mature death
  • Development of type 2 diabetes
  • Risk of breast cancer and PCOD in women
  • excess weight impairs respiratory functions leading to lung disorders like asthma and obstructive sleep apnea( no breathing while sleeping)
  • Risk of developing arthritis as a result of excessive strain on knee bones

Metabolism: How do we burn fat?

Metabolism is the chemical reactions happening inside our body that helps in extracting energy from the food we eat. You can think of metabolism as car engine which keeps on burning fuel to make your car move. Once you eat a high calorie food, the fat in it accumulates in a tissue called adipose tissue. this tissue is usually found in the abdomen region beneath the skin. Adipose tissue contains fat cells which store fat as a source of energy

As and when we eat fatty foods our body starts making space in the body to store it in muscles, liver and other organs. When a person starts exercising s/he loses energy stored in the form of fat. This energy is needed by our muscles involved in exercise like the belly. thigh biceps, triceps, etc. So our body stops storing fat as energy source and consequently the fat cells die as they are now devoid of any fat. Once our glucose levels go down in the body, it starts mobilizing energy from the fat cells .Over time our body extracts energy from our food and this time it redirects the energy to the organs tp perform their respective functions. Decrease in number of fat cells increases metabolism.

Why isn’t everybody fat ?

Everybody has the same underlying biology, still there are some people who manage to be fit even after eating the same as others. There are a few reasons for this:

Firstly, it can be blamed to genetics. Parents of lean people are lean and parents of fat people are fat. Sometimes it also happens that out of two siblings only one inherits the parents gene as we say its a 50% sharing between the siblings or non identical twins , one acquires the gene the other doesn’t. A study suggests that identical twins inherit 100% of the obesity genes from their parents(check the figure)

Secondly, lean people make conscious choices. They make sure that they burn those extra amount of calories before joining you on another McDonald ‘s party.

Thirdly, if you closely observe, they chew their food properly which aids in digestion and the brain sends signal of being full earlier. Fourthly, lean people are more active than the overweight, because they tend to fidget more and are in motion even in non exercising activities. Next reason is related to NEAT which is abbreviation of Non Exercise Activity Thermogenesis

In simple words, it is the body movement that is not considered as traditional exercise, for e.g. walking while speaking on phone, twirling your fingers, etc. According to American council of exercise, NEAT can increase your metabolism upto 50%!

Also, a starvation hormone called Leptin signals your brain whether you have enough energy to perform activities or not. Hence, lean people have more leptin production which accelerates their weight loss and controls food cravings also.


On a final note, we can say that fat loss is due to metabolism. Whether you can change the metabolic rate is a matter of considerable debate, but surely you can balance the calorie intake and increase calorie burn which can change your weight. After knowing the science behind fat loss, we can use this knowledge to our advantage and research about the stuff/personal habits that will boost our fat metabolism. To make things easier for you I have listed some things that fasten metabolism in our body:

  • Protein rich foods such as meat, eggs, nuts, legumes, seeds
  • Mineral rich foods like sea food, spinach, etc.
  • Increasing intake of spicy foods
  • caffeine (tea/ coffee)
  • Ginger
  • Apple cider vinegar
  • water
  • Oatmeal
  • HIIT workout or cardio workout
  • Vitamin -D
  • No alcohol
  • Green tea
  • Avocados

Indulge in some kind of outdoor sports activities like trekking, jogging, cycling, mountaineering, badminton, or whatever you like

So which of these foods and habits are you planning to follow or are already following ? let me know in the comments!

Thanks for reading !



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Soukhya Hegde

Soukhya Hegde

I am a biology enthusiast and love writing about various topics in biology. Through my writings,i want to make understanding biology easy!