Fat Loss Guide: Understanding Fat Metabolism & Macronutrients

Dustin Elliott
Written By: Dustin Elliott
October 13th, 2010
Updated: June 13th, 2020
Categories: Articles Fat Loss
65.5K Reads
Dustin Elliott takes a look at the science behind nutrition and supplementation and helps you to properly maximize food intake for maximum fat loss results.

Do you understand your metabolism?Fat loss has become important for all of us; whether we’re losing weight for our health, the beach, or a contest, we follow all kinds of diets and workout routines in an attempt to lose fat. Yet when people tell us what to eat, what workouts burn fat, etc; we fail to understand how fat metabolism works. This is strange considering that if you grasp an understanding for how fat is stored and utilized you will increase your chances of losing it and seeing the errors in a diet. The goal of this article will be to present you with facts on fat metabolism and dieting/exercise strategies to optimize fat loss while maintaining muscle mass.

Meal Timing

If you’ve read some of my articles previously than you are familiar with the reasoning behind having anywhere from 5-7 meals a day. This is not to speed up your metabolism but to provide proper insulin control. Insulin is responsible for pulling amino acids, glucose, and triglycerides from the blood and shuttling them where necessary. If your cells are active (working muscle, recovering muscle cells) they will be used for fuel; if they are dormant (adipose tissue), they will be stored as fat. Now to time your meals properly, you must understand the timing behind fat; triglyceride levels peak at about 4 hours after a meal, so your largest meal of the day should be early or around lunch time, and not late at night if your goal is to reduce body fat.

Knowing the timing behind insulin is important as well, insulin tends to remain elevated after a meal anywhere between 90 minutes to 4 hours after a meal, and so reducing carbohydrates up to 4 hours pre-exercise would be optimal. Exercising on an empty stomach or “starvation” cardio as it is called before breakfast in the morning is not recommended. Your body uses fuel based on what it can generate ATP (energy) with the fastest.

It begins with creatine phosphate, then glycogen, protein, then fat. Fat takes the longest to generate energy from (this is the reasoning behind low-intensity steady state cardio to use fat as a fuel source) but it provides the most ATP (it contains the most energy, which is why it is 9 calories per gram as opposed to 4 like carbohydrates or fat). So based on this, if you begin doing cardio while levels of glycogen (the storage form of carbohydrates in the body) are low, your body will begin to pull amino acids from muscle to use as fuel; only after this happens will your body begin to utilize fat.

Here are two sample macronutrient schedules based on morning training and evening training to maximize fat loss. The actual macronutrient amounts are relative based on weight and will be discussed later in this article. When zero carbohydrates are referenced, a lean animal meat source (fish, chicken breast, turkey breast) or protein powder is suggested. When low fat is being referenced, then it is best to only have your fats come from the meat in your protein source.

It is advantageous to utilize a low carbohydrate diet that employs more fats. However, for natural weightlifters the protein sparing and glycogen replenishing effects of carbohydrates are necessary to maintain muscle mass and the volume of exercise needed to burn the necessary amount of calories (1). Despite the abundance of calories contained in fat however, there is no conclusive research that shows a link between fat and improved performance.

Morning Workout:

  • Breakfast: protein, 0 carbs, low fat
  • Training and Cardio
  • Post-exercise: protein, carbohydrates, 0 fat
  • Lunch: protein, carbs, fat
  • Snack: protein, carbs, low fat
  • Dinner: protein, carbs, low fat
  • Bedtime snack: protein, 0 carbs, 0 fat

Evening Workout:

  • Breakfast: protein, carbs, low fat
  • Snack: protein, carbs, low fat
  • Lunch: protein, carbs, fat
  • Pre-exercise: protein, 0 carbs, low fat
  • Training and Cardio
  • Post-exercise: protein, carbohydrates, 0 fat
  • Bedtime snack: protein, 0 carbs, 0 fat

Total Macronutrients for the Day

As far as dividing up your total macronutrients for the day, a relatively higher carbohydrate, moderate protein, low fat diet is coming back into style for natural bodybuilders. To optimize fat loss, a low carbohydrate or carbohydrate cycling phase is still best when coming into the final weeks to optimize conditioning and take advantage of carbohydrate loading. However, continuing a low carbohydrate diet for extended periods of time for a natural lifter will almost always lead to large amounts of muscle wasting as your body will breakdown muscle for fuel.

Fat is still required in the diet to maintain healthy levels of testosterone and your dietary fat will come from your chicken, fish, and red meat once or twice a week. Natural bodybuilder Alex Stewart currently has a thread on his current progress with this style of dieting.

The reason having a higher ratio of carbohydrates is important when being involved in caloric restriction is that it can reduce oxidative stress and increase your lifespan (2). The reason this is important is because this is evidence that it is a diet that can be maintained for extended periods of time without the stress, fatigue, and cardiovascular damage of a high fat low carbohydrate diet.

Imagine if you were a natural bodybuilder preparing for a show, what would you prefer: 8-12 weeks of stressful low carbohydrate diet, or 12-16 weeks of a diet that provides you with plenty of energy, easy to find foods, and now stress until the final 4 weeks when carbohydrate cycling is incorporated. This macronutrient profile is especially effective for those who aren’t bodybuilders since finding low fat, carbohydrate foods and snacks are much easier than having low carbohydrate meals or snacks on the go.

Carbohydrates are proven for providing satiation and the feeling of fullness, however there is not enough evidence to prove that the high caloric count of fat provides the necessary feeling of fullness required for a diet (3). At 9 calories per gram it is too easy to overshoot the amount of calories you plan to provide yourself for the day, while at 4 calories per gram you could have almost twice as much carbohydrate. Any one who has been on a calorically restricted diet that incorporated fats outside of what was naturally occurring in their foods can attest to how hard it is to stop eating nuts, or to limit their scoops of peanut butter.

To calculate the number of calories to take in and the ratio of macronutrients, use a calorie calculator to determine the number of calories you require for maintenance and reduce that number by about 600 calories or by about 20%.

The diet itself will be broken up into 50% carbohydrates, 35% protein, and 15% fat. While dieting you will only need enough protein every 3 hours to maintain a positive nitrogen balance, the relatively high ratio of carbohydrates will spare muscle protein during caloric restriction and provide energy for your workouts. The timing of your carbohydrate intake will allow insulin levels to subside before your workout allowing for more fat utilization during the workout itself and the subsequent cardio.


A supplement that has much research to support it’s acute (short-term, usually 2 weeks or less) effectives are the Medium Chain Triglycerides. They are a form of fat this is broken down quickly and used readily as fuel. It was suspected that athletes with a higher fat utilization like long distance runners could benefit from supplementing with this fat but the results were inconclusive (4).

However, they are research proven to provide a thermogenic effect as a result of fat oxidation and increase fat utilization (5). This fits perfectly into the diet during the final weeks when you take advantage of the rapid, short term fat loss associated with low carbohydrate dieting. Because the effects last less than 2 weeks it is best used in conjunction with carbohydrate cycling during the low or no carbohydrate days as your supplementary fat.


The big picture for weight and fat loss is expending more calories than you take in. The instances in which this gets tricky is when muscle mass is low: where building muscle will be the focus; obesity: increasing work capacity will be the focus; and states of low metabolic rate from lengthy dieting: incorporating new strategies like cheat meals and increasing cardio are key. The best way to know what works, and to save yourself from having to try every type of diet; is to develop a better understanding for how fat works and how it’s metabolized. Then once you’ve got the timing, meal composition, and total calories down…the rest is just all about training and commitment.

Dustin Elliott is the Head Formulator for Betancourt Nutrition.

  1. Louise M. Burke; Bente Kiens; John L. Ivy. Carbohydrates and Fat for Training and Recovery. Journal of Sports Sciences, Volume 22, Issue 1 January 2004 , pages 15 – 30.
  2. N. Barzilai, C.Gupa, Department of Medicine, Albert Einstein College of Medicine. Revisiting the role of fat mass in the life extension induced by caloric restriction. J Gerontol A Biol Sci Med Sci (1999) 54 (3): B89-. doi: 10.1093/gerona/54.3.B89
  3. John E. Blundlell, Jenny I. Macdiarmid. Fat as a Risk Factor for Overconsumption: Satiation, Satiety, and Patterns of Eating. Volume 97, Issue 7, Supplement, Pages S63-S69 (July 1997)
  4. Damien J. Angus, Mark Hargreaves, Jane Dancey, and Mark A. Febbraio. Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance. J Appl Physiol 88: 113-119, 2000;8750-7587/00
  5. Marie-Pierre St-Onge, Robert Ross, William D. Parsons and Peter J.H. Jones. Medium-Chain Triglycerides Increase Energy Expenditure and Decrease Adiposity in Overweight Men. Obesity Research (2003) 11, 395–402; doi: 10.1038/oby.2003.53
Posted on: Mon, 12/08/2014 - 04:01

this is a dope article. very informative, props.

Posted on: Mon, 12/08/2014 - 02:14

Interesting though somewhat confusing article. Simply put: your body will utilise DIETARY energy sources first, that is simple sugars, fats, complex carbs, then protein as it's the most complex to process. Eliminating fats is a sure fire recipe for health issues later (neurological & cardiovascular especially, & hormonal for women), but a low carb/fat diet will encourage the body to shift fat stores for energy & make better use of your protein intake. More fresh/steamed veg & more water are essential ;-)

Posted on: Wed, 12/26/2012 - 21:19

Hi Steve,

How do you find the energy required to lift during a session? Do you do light sets and high reps or just don't go very heavy?

Posted on: Tue, 12/25/2012 - 11:57

It's not possible not to have carbs before weight lifting. You can't utilize your stored body fat for energy in such a short amount of time (during weight training session). You need the energy that carbs provide you with. You should consume carbs about an hour prior to lifting... How can you say "0 carbs" before workout?!

M&S Team Badge
Posted on: Wed, 12/26/2012 - 09:35

Hi Dave,

Just sharing my personal experience. I haven't eaten carbs for at least 8 hours prior to lifting in about 5 years.

Posted on: Mon, 05/07/2012 - 17:02

too much 'science'. u need to hit the plates hard and for long. there is no shortcut in progress. meal timing, no timing blah blah..

Posted on: Wed, 07/13/2011 - 21:19

So im confused. Which is better for dropping body fat%, HIIT or low-intensity steady state cardio??

Posted on: Mon, 07/11/2011 - 18:53

i find it almost impossible to not take in carbs before a workout and late night snack, what types of food would you suggest, everything i run into has carbs!

Posted on: Sat, 07/09/2011 - 19:41

Is it okay to follow this plan on my cardio days, because I lift on other days.

Posted on: Wed, 04/20/2011 - 15:57

Great article. Just what I was looking for.

ben g
Posted on: Fri, 04/08/2011 - 09:28

This was awsome post.Its helping with my training and iam training to be trainer myself this helps with so many things.Thanks guys keep up the good work

Posted on: Tue, 02/01/2011 - 16:57

What would be the ideal protein,carb,fat meal plan for this routine?Waking at 4:30am with cardio for 45 min. with breakfast within 1/2 hour afterwards. Break with food at 9:00. Lunch 11:00. Break with food 1:30pm. snack 4:30. Weights at 5:30 for an hour. Dinner at 7:30pm and in bed around 10:00pm. Can't really change the routine with work and kid's schedules of activities.

Posted on: Tue, 04/05/2011 - 20:55

I have the same type of question. I do cardio early morning and lift weights in the after noon.

Posted on: Tue, 02/01/2011 - 12:03

"Fat takes the longest to generate energy from (this is the reasoning behind low-intensity steady state cardio to use fat as a fuel source) but it provides the most ATP (it contains the most energy, which is why it is 9 calories per gram as opposed to 4 like carbohydrates or fat)."

First off thanks for this post its very informative for a guy who's new to weight lifting and cutting etc. Is the word "fat" at the very end of the paragraph not meant to be "protein" its just i was a little confused sorry if this is wrong.

Posted on: Mon, 12/10/2012 - 02:53

Ya you are right.

Posted on: Mon, 01/03/2011 - 00:02

can you give me a few examples of things with protein and zero carbs??

Posted on: Sun, 11/07/2010 - 07:49

I've always been a fairly active person being in the military. My workouts have always consisted of mostly CV and very little resistance work. About 8 months ago I broke both my wrists and I fell out of my routine and put on some weight (fat) I'm now 16.5%bf instead of my usual 11%. 8 weeks ago I started a new routine heavy on the resistance training and CV, I've noticed masive increases in strength, but I cant seem to shift the fat. Can you recommend an eating style to accelerate my fat loss? My priorities are to lose the excess fat, then swap eating styles to a muscle mass increase diet. I don't mind putting the muscle increase on hold for a couple of months while I lose the fat.


M&S Team Badge
Posted on: Sun, 11/07/2010 - 11:12
Posted on: Thu, 10/21/2010 - 03:40

how can i increase my metabolizem

Posted on: Thu, 10/21/2010 - 12:54

I have found the best way to increase your metabolism is through a variety of things. Just eat frequently (5-8 meals a day is the widely accepted mark). Be sure to get a good cardio routine in too, whether its spinning, running or jumping on the elliptical it is all beneficial for your health and metabolism.And of course, lift weights. In addition to increasing your metabolism over time, hitting the weights, especially heavy compound movements like squats, deadlifts and benching will also increase your body's output of HGH and Test for a short period of time, which we could all agree is beneficial.

Posted on: Thu, 10/21/2010 - 03:34

I have problem in the fatloss I have 40 KG fat according body mass analyasis and free fat mass 90 KG
My training is morning 3 time aweek in goldsgym in egypt for 2 years ago
what i can do for that

Posted on: Wed, 10/20/2010 - 14:33

Awesome article bro, goes into a lot more depth than most "Fat loss" articles.