40 Day Fat Loss Challenge

At the beginning of last year (2014), I challenged myself to get in shape for my first ever NPC bikini contest and reached that goal after 5 months of training (July 2014).  Since then, I’d been pretty much slacking on the diet and workouts, but by October 2014, I was not liking how I felt physically when I had gotten used to being in great shape.  My weight was creeping back up and my muscle was turning into fat.  In November, I started back with my trainer and by December had started embracing my bikini meal plan again, but not nearly as strictly and not without lots of “cheats”.  It was the holidays after all.  And I like to eat as much as the next person.

40 Day Fat Loss Challenge
Now that we are back at a new year, my husband has surprised me by entering our gym’s 40 Day Fat Loss Challenge.  And he’s determined to win.  His friend won last year and, being an investment banker and “numbers guy” though not a nutritionist, has come up with his formula for what it would take to win- win being lose 50% of your body fat in 40 days.  To be clear, our friend came up with this plan, not my husband.  Last year, there were two people who lost 48%, so he’s considering that losing 50% would win the contest. 
I’m NOT saying this is the healthiest way to go or that you should follow this type of challenge, but what HAS been interesting to me is the numbers and science of it all.  We KNOW that to lose weight, we have to eat less than we burn, creating a caloric deficit.  You can Google “weight loss calorie deficit calculator” to find online calculators to help you figure out how many calories you should eat to lose weight.

It’s amazing to see on paper how many calories you can consume, in what quantities, and how much you need to burn through exercise (tracked via a heart rate monitor) to achieve a desired outcome; weight and fat loss.

Body Fat Test Results
My trainer measures my body fat with calipers and I’ve always wondered how accurate the result is. I found out recently he’s been pretty much right on.  Last Thursday, he measured me at 24% body fat.  I went that night to the gym for the challenge and was measured, like everyone else, with the InBody Analyzer at 23.4% body fat.  I weigh 111.6 pounds.

So, back to the friend and his data.  
The Fat Loss Plan on Paper

Below, is just an EXAMPLE of what I would have to do for the next 40 days to get down to 16% body fat.  I’m showing you this just so you can see how the numbers play out.  Of course, I’m eating way more calories than this (in fact, when I was training for my bikini contest I was eating about 2000 calories a day!).  I just asked our friend to input my numbers so I could see what they looked like.

  1. My BMR 1208 (Basal metabolic rate is the minimal rate of energy expenditure at rest) 
    Fat loss 31.6% (23.4% (current) – 31.6% = 16% target fat percentage) 
    Daily calories:  870 divided by 6 meals = 145 calories per meal 
       (carb 59 grams, protein 57 grams, fat 29 grams)
    Energy output:

    BMR  1208 + Exercise 505 = Caloric output 1713

    Caloric output 1713 –  Required deficit 842 = 871 calories per day 
    (Note: He has me losing 31.6% of my body fat because that’s about what the women’s winner did last year.)
    As soon as I saw that to lose 8% body fat (31.6% of my current body fat; i.e. go from 24% to 16%) in 40 days, I’d have to burn 500 calories through exercise 6 days a week (I just got my heart rate monitor, so I’m not even sure how many calories I burn during a workout, but I’m anxious to learn) AND have a calorie deficit of 842 calories per day, meaning I only eat 871 calories per day, I knew that was too low for me in terms of calories.  
    I modified my meal plan to about 1250 calories per day, and after 2 days, found I was still hungry, so I’m upping it even more.  I don’t want to lose muscle along with fat, so I know I still need a sufficient amount of calories, along with carbs, protein, and fat.  As soon as I figure out my happy medium in terms of calories a day and wear my heart rate monitor during a workout, I’ll give you an update on those numbers. 
    Also, I’m not trying to win this 40-day contest, just continue to see results from my workouts, lower my body fat and lose about 6 pounds, so I don’t have to be THAT strict with my calories.  I am curious to see where I’m at in 40 days though.  
    We are setting up my heart rate monitor tonight, so I’ll be sure to tell you how I like it.  Have you used one?  

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Meet Megan

Hi! I’m Megan, mom to a thoughtful teenager and spunky young girl. We call Houston home and recently moved into our dream home. I traded my lawyer hat to become a full-time blogger in 2010. I love sharing my passion for affordable fashion, home decor, organization, & fitness to help inspire you to take care of you!


  1. Very interesting..I never looked into the science of it all. I just bought a heart rate monitor and love it! Although I am pregnant now it still helps me keep track of how much I'm burning – while also making sure I don't get my heart rate too high during pregnancy. I love to eat and easily let myself overindulge so having it helps keep me on track. 🙂

  2. I have a Polar RS300X Heart Rate Monitor Watch and love it! It works awesome and was not to expensive… it is currently around $79 on Amazon!!
    What brand did you get? Keep up your awesome work! I love reading your blog!

  3. I wore a heart monitor a number of years ago when I was working with a trainer, but I don't hvae one personally. I've been lazy since we adopted our daughter last year so one of my goals this year is to get back to working out. We have equipment in our garage so I have no excuse! I've been getting in 4-5 workouts a week. The jumping lunges are killing me right now, haha. 🙂 Hubby and I also started the 21 day Sugar Detox on Sunday – I just posted the first week meal plan on my blog. Since we pretty much each Paleo (not completely – we do have yogurt and kefir – both that I make – it's SO easy!!) so we're doing the Level 3 challenge. It's definitely restrictive – I LOVE to eat and have a huge sweet tooth, but I just want to get back off sugar after eating yummy desserts and cookies over the holidays! 🙂 I don't have a fat loss goal, but I am working on doing more pullups!
    Good luck Megan – to you and your hubby! 🙂

  4. You are truly inspirational! I am embarking on my own fitness journey (man is it tough after baby #2!)! I recently became a Beachbody coach with the hopes that I can inspire women (especially busy moms) to take the time they deserve and workout. I am hoping to host some Facebook challenges in the near future to create a supportive group for women to join and encourage one another to lead healthy lifestyles! I can only hope that I will be as inspiring as you are!


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