Starting a Fat Loss Program Part 3 - Metabolism Basics - Calorie Deficits

Welcome to Part 3 of Starting a Fat-loss program. Today we are going to focus on creating calorie deficits and actually start burning some fat! In part 1 and part 2 of our fat-loss series we learned the foundation for metabolic energy balance and how to calculate our daily energy needs, so check back to those articles if you need to catch up.

When it comes to losing body fat consistency is paramount. You need to maintain a consistent calorie deficit daily. When you do, you are rewarded by dropping pounds of unwanted fat on a weekly basis. When you don’t, your results will vary and frustration will take over and have you questioning your sanity and eventually your commitment will falter.

To begin let’s start by examining the following chart.

Calorie Deficit per day


Calorie deficit per week


Pounds lost per week

1/2 pound
1 pound-500
1 1/2 pounds
2 pounds

By reviewing this table we can determine how big of a daily caloric deficit we need to create to lose a desired amount of weight each week. Be aware that not all weight loss will come from fat alone particularly as you get into more aggressive calorie cutting, some of the weight you lose may come from losing muscle. To prevent this we recommend regular exercise which we will explore in depth in later articles.

When choosing a daily calorie deficit you should consider your gender and age as factors too. Men and Women have different metabolic rates and everyone’s B.M.R. declines with age. I would recommend most people to start with a half pound to a pound of weight loss per week as a good starting point. If you want to lose fat more aggressively consult with a certified fitness professional who can help you increase your calorie out put and allow you to cut more calories with out leaving you dangerously low on calorie consumption. I would never recommend anyone ever eat less that 1200 Calories for a female or 1500 Calories for a male and before you start any fat-loss or fitness programs please consult with your doctor.

So for myself I am currently trying to lose 1 pound of body fat per week through diet and exercise. Which means I need to bring back my formula from part 2 and reverse engineer it to see how many calories I can eat today.

Energy Expenditure( BMR* + Activity + Exercise ) - Calorie Deficit = Energy Intake Goal( Food )

Filled in it looks like

Energy Expenditure( 3105 ) - Calorie Deficit( 1000 ) = Energy Intake Goal( 2105 )

Now I know that if I eat roughly 2100 Calories today I am on track to hit my goal of losing 1 lb of body fat this week. Again if this all seems tedious, it is only because I am laying this out manually to help illustrate the founding principles of fat loss. In practicality, I use a phone app and wearable device(think fitbit) to do the calculations for me automatically each day.

Remember for this formula to work as expected you need to hit your caloric deficit each and every day of the week. This means tracking your food input and output and adjusting your eating to your activity level for the day.

So this brings us to the end of the metabolism basics part of our series on starting a fat-loss program. You now have a solid foundation of managing your body weight through understanding your metabolism.

In our next article we will begin the practical application of these foundations and will look at creating a meal plan based on our nutrition goals and your personal metabolism.


about the author


is a certified member of the Canadian Association of Fitness Professionals and C.E.O in the software development sector. With a passion for personal fitness and helping others achieve their best health and performance Aaron coaches nutrition and exercise programs at Elite Personal Training in London, On.