How to Lose Body Fat, According to Science

how to lose weight according to science

Science-based Weight Loss Tips

We explain how to lose body fat from a scientific standpoint, and offer simple science-based advice on dieting, weight loss, and exercise.

Below are some science-based weight loss tips. Follow all these pointers and learn the details (like how essential acids, metabolism, and hormones like insulin work) and you’ll be well on your way to losing weight in a healthy way. You’ll notice the basics are common knowledge, but the reasons why each is important aren’t commonly known.

TIP: Don’t forget, every body type is different and fat is an important part of our biology and diet. We can’t eliminate fat and we don’t want zero percent body fat, this is diet advice for seeking a healthy weight at a healthy pace.

  1. Drink water. You are a water-based organism, and all the food you eat is too. Thus this is all predicated on you hydrating effectively. The human body is about 50 – 75% water, this includes your fat cells, although fatty tissue contains less water than lean tissue. All food contains molecular chains of C, O, H, and N atoms, so water, carbon, and nitrogen. Water is vital to the metabolizing process.[1]
  2. Eat a balanced diet. Balance macronutrients (fats, carbs, proteins; including essential amino and fatty acids) and micronutrients (vitamins, minerals, and other compounds contained in food like cholesterol), and focus on nutrient dense foods. Complex carbs (found in veggies, whole grains, beans, nuts, etc.) are your friend. “Bad fats” (saturated and trans), simple sugars (refined sugar or fruit sugars), and processed foods (“junk foods”) are your enemy. Our body gets all its energy from sugars and acids found in macronutrients, micronutrients, and water needed for the metabolizing process that turns food into usable energy. The only things humans NEED from a biological standpoint are essential acids and micronutrients. Everything else gets converted to glucose or used for metabolism and digestion. Learn more about fats.[2][3]
  3. Eat small and frequent meals to ensure the calorie stores (glycogen stores) in your muscles and liver stay low, and your metabolism stays high. Small meals will help ensure your body burns fat as energy, instead of storing energy in your liver and muscles. Learn more about losing weight.[4]
  4. Avoid late night snacks to give your body time to burn calories. When you create longer fasting periods, and when those periods include sleep, your body gets a chance to create fat burning hormones that help you to burn body fat faster. In words, total calories in and out is the key, and this part helps with the out!
  5. Avoid spiking your blood sugar to ensure glucagon production (not insulin production). Glucagon triggers your body to use stored energy, and insulin spikes cause your body to suppress satiation (the feeling of being full), feel hunger, and store fat (insulin tells your body to store fat). This will help you avoid storing glucose as fat. Learn more about insulin, calorie stores, and weight loss.[5][6][7][8]
  6. Create a daily calorie deficit considering your personal physiology; consult a health professional. Weight is based on caloric balance, and thus losing weight requires a calorie deficit. Eating too few calories will cause your metabolism to slow down and can result in health problems. You need calories to live, so it’s all about balance.
  7. Exercise using a mix of cardio and weight lifting. Avoid under or over exercising, and consider cheat days. Never overwork your body. See more advice below and how cheat days work.
  8. Eat protein after working out. Wait about 45 minutes after working out to eat a meal, and make sure you eat enough complete proteins containing essential amino acids within 48 hours of working out to ensure new muscle is synthesized instead of old muscle being used as energy.

Discover the Science Behind Body Fat & Weight Loss. This video explains the science of weight loss well. Calorie deficits aside, the basics all have to do with the way our bodies store and use glucose, glycogen, and the acids, and how our hormones (specifically insulin and glucagon) relate to this. The rest is a matter of nutrition, metabolism, and exercise.

That is all there is to it. However, it’s also important to consider:

A Calorie Isn’t Just a Calorie

The calories on the label don’t equal the calories you will store exactly. Even though the modern labeling process uses a fairly accurate scientific system that factors in digestion, it is still only an estimate.

In general, it takes more calories and time to burn proteins, than complex carbs, than simple carbs, than fats . This is called “the thermic effect of food.”

It works like this. Protein takes the most energy to digest (20-30% of total calories in protein eaten go to digesting it), carbohydrates (5-10%) and then fats (0-3%). The table below shows a more detailed general count. On the left hand is how much energy it takes to burn a substance, on the right is how much energy humans can synthesize from the substance:[9][10]

Food component (source) Energy density
kJ/g kcal/g
Fat 37 9
Ethanol (drinking alcohol in Beer, Wine, etc.) 29 7
Proteins 17 4
Carbohydrates 17 4
Organic acids (in preservatives, supplements, and animal feed) 13 3
Polyols (sugar alcohols, sweeteners; essentially “fake” sugars) 10 2.4
Fiber (soluble fiber is 2 kcal, insoluble is 0; both are 8 KJ) 8 2

TIP: All the other nutrients in food are noncaloric and are thus not counted, although one shouldn’t ignore the micronutrients or the acids in their diet.

Metabolism Matters

Metabolism describes the process of converting food into usable energy. In general, when our bodies and minds are active, meals frequent, and water and nutrients plentiful, our bodies will metabolize fat and other energy more quickly.

In general, 3,500 calories equals about 1 pound of fat. When you start your diet, a 3,500 calorie deficit will equate to 1 pound of fat loss. If you create a 500 calorie deficit each day, you’ll lose a pound a week. However, as your body acclimates to the new routine, that number nearly doubles. In 12 months it’ll take roughly 7,000 calorie deficit over time to equate to 1 pound of weight loss. This can be offset somewhat by “switching up your routine” and utilizing “cheat days.” See NIH Body Weight Planner added to USDA SuperTracker food and activity tool.

TIP: There is no perfect theory of fat, there is what we know (AKA the facts like the ones on this page) and then there is what we understand based on that. With that said, anyone interested in the nature of fat and dieting should check out The Secret Life of Fat by Sylvia Tara PhD. Sylvia not only describes the nature of fat in detail, she also gives some interesting diet advice (such as suggesting that waiting longer hours in between one’s last meal and first meal is a key to weight loss due to fat burning hormones we release while we sleep, as noted above).

TIP: If you try to undercut your calories too much, your body will react by tightening up your metabolism. If you eat too much, you will store excess fat, and your metabolism will tend to increase. If you don’t take in a balanced diet with lots of water, your body won’t have everything it needs to metabolize. This could also cause your metabolism to tighten up.

How Does Exercise Impact Weight Loss?.

Diet and Exercise Advice: Introduction

Even though weight always boils down to calories stored versus calories burned, weight loss isn’t just about what you eat, or how much you exercise.

Weight loss depends on understanding what foods to eat to ensure the right nutritional balance for you. You will need to know how to create a calorie deficit for your body type, realize the way your metabolism works, and exercise based on your body and the body you want. You also need to know how hormones like insulin can work for you or against you.

With that said, I’m going to share a basic diet and workout routine that helped me lose 80 pounds.

I know everyone is different, and I respect that medical conditions can make weight loss harder. Follow your instincts and professional medical advice over online weight loss advice.

If you are interested, ask me questions, I’ll be happy to answer any question specific or general to the best of my ability.

Diet and Exercise Advice: A Diet that Creates a Healthy Calorie Deficit

My personal diet and exercise routine was designed to create a calorie deficit in a healthy way. I lost 80 pounds with this, so I know it works for me. You would want to tailor this to suit your needs and consult a health professional:

  1. 30 min – 1-hour workout 3 – 5 times a week. 5 minutes of stretch, 5 minutes of cardio, 20 minutes of high rep non-stop workout, followed by 20 minutes of cardio (the weight lifting is in the middle to promote metabolism). Do that workout about 5 times a week. The minimum is about half of this on all accounts. As a bonus, include swimming or another full body exercise as cardio. Try to keep active for as well. This will help you get a slim shape rather than a bulky one. If you want to bulk up, focus on lower rep higher weight workouts.
  2. 5 – 6 meals a day and lots of water. For me (5′ 7” male) it was about 150 – 250 calories a meal. The total calories you need in a day is specific to the person. I am very tempted to give you a range, but it’s better if you just take a look at the official suggestions by the USDA. See Estimated Calorie Needs per Day by Age, Gender, and Physical Activity Level. Trainers and official sources will almost always tell you to eat more calories than needed, and that will make it really hard to lose weight. Also, people tend to have problems being honest with themselves. I strongly suggest weighing food rather than looking at serving size and understanding how labels work. The best metric to judge your success by is the scale. If you aren’t losing weight, you ARE either gaining muscle mass, which weighs more than fat or are eating too many calories for your body type and exercise regime. Of course, you may have a health issue that should be factored in.

The following is advice that will help ensure that your routine works.

  • Eat foods high in fiber and nutrients. Make sure you consume balanced, macronutrients and high micronutrients. You also need to drink lots of water to keeps your metabolism going and fill up. Whatever you do, don’t take out an entire food group or ignore the essential acids, vitamins, minerals, or water.
  • Limit drinking alcohol. Also, if you want to see results, then limit salt as it makes you look bloated.
  • Consider cheat days. If you go long enough, cheat weeks for working out are also useful. Tricking your body works well, especially in the short term. Part of what we are doing with the small meals is fooling ourselves into feeling full.
  • The worst thing you can do, aside from lack nutrients, is spike your blood sugar and over-fill your calorie stores.

If you give yourself a calorie deficit aimed at losing between 1 – 2 pounds a week, you should lose weight fairly consistently, at least until the last 10 or so.

In summary, you need small healthy meals, lots of water, and regular exercise to keep your metabolism going. The hardest part is the initial willpower. Once you are used to the routine, it gets easier.

TIP: Consider weighing your meals for a more accurate calorie count, also remember: calories on the label don’t equal calories stored. So if you go for a diet rich in simple carbs, you’ll need to take in fewer calories than if you err toward complex carbs, fiber, and protein.

TIP: For other science-based weight loss facts see 67 Science-Backed Ways to Lose Weight. and 57 Ways to Lose Weight Forever, According to Science.

Anatomy and Physiology of Metabolism Nutrition. This is the real health science answer to how weight loss works. Yes. its a long video, but it has to include a whole field of science.

Article Citations
  1. How Much of Your Body Is Water?
  2. Macronutrients
  3. Micronutrients
  4. Glycogen
  5. Can Fats Be Turned Into Glycogen for Muscle?
  6. Low Carbohydrate Dieters: Beware of High Protein Intake
  7. Glucose
  8. Glucagon
  9. A calorie isn’t a calorie
  10. Food Energy

Author: Thomas DeMichele

Thomas DeMichele is the content creator behind,,, and other and Massive Dog properties. He also contributes to MakerDAO and other cryptocurrency-based projects. Tom's focus in all...

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