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THE SCIENCE BEHIND WEIGHT LOSS

Updated: Dec 21, 2022



Despite the thousands of diet books and strategies and guru’s on the internet, there are some fundamental rules to fat loss which simply CANNOT be avoided.


Rule #1 You must create a calorie deficit to lose body fat

Rule #2 You must create a calorie deficit to lose body fat.

Rule #3 Review rules #1 and 2


If you feel you are not losing weight and are in a calorie deficit, guess what? You are not in a calorie deficit, (true for 99.9% of all mammals)


Do we have exceptions to this rule, yes, what would a rule be without exceptions? To the best of my knowledge, here they are.


Teenager with very high levels of HGH


People using drugs (Anabolic steroids, HGH and other drugs such as clenbuterol)


Newbies who have NEVER trained before can for a short period of time loose fat and gain muscle on a diet that is close to ‘’even’’- Meaning not a significant surplus or deficit.


Calories, calories , calories,….


You might hear the quote ‘’counting calories is for losers’’ but typically those are people that are on a crazy restrictive diet where they do not need to count or they are often hypocrites that count their macros. If you are counting your protein, carbs and fats, guess what, you are counting calories…


As a quick guide before we go further, here are the calories contained in 1 gr. of each macronutrient family.


1gr Of carb = 4 calories

1gr of protein= 4 calories

1gr of fat = 9 calories


Fats and protein are essential from proper health and carbs are the luxury macro where you can get away with barely eating any and you will be able to function through the production of Ketones. You will also have super low insulin spikes so those who are on a ketogenic diet (and not overeating) will have a lot of ease loosing fat. In fact, since insulin is the ‘’storage’’ hormone, anyone who drastically reduced their carbs within a calorie deficit is setting themselves up for fat loss.


Energy balance (calories in vs calories out)


If input is the same as the output, you maintain. If input is greater, you gain and if input is less, you lose.


Your output is a combination of your BMR (basal metabolic rate) – the energy you exert by just breathing and keeping all bodily function going + additional expenditure such as exercise and any form of physical activity. BMR is what is need – just to keep the lights on,… no movement, no talking…


NEAT: Non Exercise Activity Thermogenesis comprises activities such as talking, laughing moving around, walking to the counter


EA: Exercise activity


TEF: Thermic Effect of Food: Depending on what you eat, this would probably average out to 10% of the calories you consume. That number goes up the more complex the food or the more complicated it is to digest. TEF of protein will be much higher than TE of a glass of juice.


If we want to lose fat, the output MUST exceed the input. This can be accomplished in two ways; Do not change your diet and increase the output or do not change the output and lower the input. Or some can do both for optimal results.


With that said, the biggest control you have, in my opinion is the amount of calorie you consume. So what to do??


Find your maintenance and drop 500 calories a day, and you will tip the scale towards weight loss. Or if you increase you EA by 500 calories, same/similar impact. A bit better in my mind but more but obviously requires you to sweat a bit more J


TEF: If you were low on protein, ex 50gr. a day and move up to 125gr day and you will increase thermogenesis because the digestion of protein has a much higher thermal effect. So for those who argue that a calorie is a calorie, perhaps when it’s in your mouth, yes. But at the end of the day, sorry, the effort that it takes for your body to digest that calorie counts and will impact weight loss or gain.


To give you an idea of the TEF

Protein: 30% TEF

Carbs: 6-8 % TEF

Fat- 2-3 % TEF

Fiber: 30%


So if you are eating a high protein and high fiber you will have very high TEF impact. You must expend more calories to extract the nutrition and process it out of your body. Please keep in mind that all the tools online to measure your BMR are just estimates. Harris benedict, muller equation, etc are just estimation and NOT 100% accurate for YOU. You need to track your macro to really know.


Calories on the labels: I have bad news for you, these are estimates too and can be off by 10-20% so if you are basing your numbers on labels, you can be off. If you are consuming a lot of fruits, then you are def. off because these vary the most. The sweeter they are, the higher they are. We’ve all has instances where a batch os strawberries is the absolute sweetest we have ever tasted!! The will have more sugar than the crappy, offseason strawberries you had last month.


So can you eat as much protein and fibre and never lose weight, NO. Although it is harder to store fat from a diet that consists mostly of protein and high fibre foods, it can be done. That being said, it a lot harder to overheat chicken breast and broccoli vs overeating cheesecakes and potato chips. What would likely happen, since it is harder to store protein as fat is that they will create a calorie cushion and make it easy for the carbs that you consume that day to then be stored as fat.


Another important aspect to consider is that maintenance calories can and will change over time. You can hit plateaus because of changes to your NEAT changes to your BMR and metabolic adaptation. TEF can also go up or down as you become more/less efficient at digesting certain foods. EA will also go down if you are doing the same cardio all the time. Your body will simply get more efficient so the great benefits you have at the beginning of your new diet and program might not be so great 3 months after.


So then, as you hit a plateau, you are left with 2 choices:

  • lower calories again

  • Increase EA.


You don’t want to be lowering your calories every time you hit a plateau because that will eventually cause muscle catabolism, lower you BMR and make it even harder to lose weight down the road. Anyone who wants to lose weight needs to hang on to all the muscle they have as muscle mass if one of the primary drivers to you BMR. The more muscle you have, the higher your BMR . Option 2 or a variation in the type of exercise you perform is often a better option when approaching dangerously low calorie counts.


Fat metabolism


How does fat move around in the body?


Fat digestion is quite different than carb/protein digestion and most of it occurs in the part of the intestine called the duodenum. Your fat then forms chylomicrons and will circulate in your blood stream having access to and proving energy to organs and tissues in the form of fatty acids.


Fat is composed of three glycerol molecules and of often referred to as triglycerides. In order to break fat down, our body uses the enzyme called lipase to break down the fat into individual fatty acids. These fatty acids can then exit the cell and either be burned for energy or repackaged into triglycerides if there is already sufficient energy in our body. Ex. Even if you have free fatty acids ready to be burned, if you just ate a box of donuts, your body will use the sugar from the donuts before tapping into those fatty acids.


Some scenario/examples


High fat and low carbs;


You will have a lot of chylomicrons and low insulin (storage hormones) So you will be burning lots of fats and will have increase fat oxidations but also a lot of fat storage. Please keep in mind that despite the fact that insulin makes fat storage a lot easier, we do not need insulin to store fat as bodyfat. So yes, you are burning more fat but you are also storing more fat.


The net balance will determine if you will be gaining fat or loosing fat. If you are in a high fat diet and in a caloric surplus, you WILL store fat.


High carb diet in a caloric deficit.


High insulin but very few chylomicrons. You will have decreased fat oxidation but you will also be storing less fat because you are consuming less fat. Can you store carbs as fat, yes through a process in the liver called dinovolipogenesis (DNL). But the rate is not very high.

Just because your insulin is high does not mean you are storing a lot of fat because if you are barely consuming and fat, there is not that much fat to store. The rate of DNL in a calorie deficit, low fat diet in very minor. But it does mean that the fat you eat is more likely to be stored as fat.


Ex. 200g of fat, You will have very high fat oxidation and high amount of fat storage BUT if you are in a calorie deficit, your fat oxidation required for energy will outweigh your fat storage.


Now lets look at a high 200g carb l and ow 40 g of fat diet


Decrease fat oxidation, increased carb oxidation. But the increase in insulin will mean that more of the fat you ate will be store as fat. You stored less fat in this high carb low fat diet because your fat was so low.


So although the rates of fat oxidation varies from a high protein/low carb /high fat diet vs a high carb/low fat/mod protein diet, the end results is practically the same. A deficit remains a deficit and this is directly dictated by energy balance and the amount of calories we consume.


How different nutrients flux


Carbs get converted by the liver to glycogen and can then be stored in the liver and in muscles or converted to fat through DNL. Of course, it can also be delivered to the blood stream.


Fatty acids come through the lymph system and then into the blood stream. In the liver, they can be used for fuel and they can also be repackaged into DLDL, HDL and LDL, These repackaged lipoproteins can then be transported to tissues within the body.


Ketones: When you are breaking down fat and have very little presence of glucose available, your body starts to produce Ketones which can fuel your body with energy. Those who are on a Keto diet know this very well.


Understanding protein and amino acids. (Proteins are formed by the combination of individual amino acids)


Muscle breakdown is always occurring and muscles synthesis is also always occurring. If there is more break down there will be a net muscle loss and if there is more synthesis than breakdown, there will be a net muscle gain.


In a negative energy balance, there will typically be more flux of amino acid breakdown in order to maintain blood sugar levels. 60% of amino acids are gluconeogenic meaning that they impact insulin and blood sugar. Gluconeogenesis is simply the formation of glucose from other molecules, mainly amino acids. So this is why in a ketogenic diet, you can’t have a high protein diet become it will increase you glucose.


Weight loss vs Fat loss


What the scale is not telling you:

For those who do not train, they tend to lose 60% bf and 40% lean body mass. Lean body mass is NOT the same thing as muscle. LBM is ALL non body fat tissue. That includes bone weight, organ weight, muscle weight. Skeletal muscle might just be 10-20%.


Why are they loosing so much lbm:

When you lift weights you breakdown muscle and there is greater emphasis from your body to repair and rebuild, thus fluxing amino acids towards the muscle. They are more at 80/20 because it will want to remodel muscle tissue. Those who lift weight will simply retain more muscle mass while dieting. For those who are just starting, even more…the signal will be stronger. If you are looking at natural bodybuilders who are at their peak and have been training for a long time, they will likely be around 70% loss of fat ,30 % loss of LBM as the signal is not as strong anymore..


P.S. A lot of your body mass is water, roughly 70%…don’t freak or celebrate to early .

If we lose weight, we loose from either adipose tissue or muscle tissue. What we do and eat will impact this. Good diets need to spare lbm and maximize adipose loss. Why, maintaining lbm will allow you to burn more calories as your bmr will be higher.

Looking at the studies, here are some of the things we can do

  1. Do not lose weight to fast. If you lose more than 1 % week, you will lose too much muscle

  2. Eat a higher protein diet. .8 to 1.5gr/ pound of LBM

  3. Set your protein first, then decide on the other macros: If we look at most studies depicting different ratios of high carbs/ low fat vs high fat/low carb, there doesn’t appear to be a significant difference in results regarding lean body mass retention or metabolic rate when eating at an energy balance.

  4. Hang on to your muscles: If medically cleared, add resistance training to your routine

  5. Make sure the food you eat in nutritionally dense. Meaning packed full of vitamins and minerals.

  6. Avoid all process foods/oils/sugars

  7. Stay focused and disciplined!!

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