How I calculated my real RDI and got my scale un-stuck

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Joined: Apr 12
Posts: 77

Posted: 01 Jun 2012, 12:30
I’ve noticed a lot of questions about calculating your RDI, and after some experimentation and discussion with my doctor, I’ve arrived at a formula that helped me better adjust my calories to achieve my weight-loss goals. I wanted to share it with you.

DISCLAIMER: This is not a quick answer. It takes experimentation and testing! But if you’re counting calories anyway, you might like this feedback, and I found the FatSecret app to be enormously helpful.

I started by weighing myself at a regular time each day – when I first woke up. I am trying to be as consistent as possible to get more accurate feedback. Also, I’m trying to “ignore” that number as a sign of “real progress” because I know my weight fluctuates. (I’m just gathering data here.)

I started at 222 lbs, and FatSecret calculated my RDI to lose 1 pound per week based on my normal (fairly sedentary) activity at 1,800 kcal/day. This implies it thought I was burning about 2,300kcal/day doing normal activities, since 3,500 calories = 1 pound of body weight, and it was recommending I create a calorie deficit of 500 kcal/day = 3,500 kcal/week.

I set up my activity counter for a “typical day” – that is 8 hours sleeping, 7.5 hours “resting,” 30 minutes of housework and 8 hours of desk work. Here, FatSecret estimated I was burning 2,770 kcal/day. So one could conclude that if I stuck to my sedentary lifestyle (I work from home at a desk) and ate 1,800 kcal/day, I would actually lose 2 pounds per week (~1,000 kcal/day deficit, for a total of 7,000kcal/week).

Not so fast. That did NOT work! In fact, every time I’ve done that, my weight has gone up.

I know that diet and exercise must go hand in hand, so I have committed to walking 3 miles per day at a brisk (3.5-3.8 MPH) pace. That usually pushes me over 3,000 kcal/day burned. I only log exercise that makes me sweat—housework (with two little kids, there’s a lot of picking up), walking on the treadmill or in my neighborhood, etc. I get in at least 18 miles per week, and I am also using 2-lb weights to tone my arms while on the treadmill.

I am counting every calorie as well. One FatSecret member logs all of her BLTs (bites, licks and tastes). A lick of frosting might have more calories that a whole cup of berries!

Now, after doing this for 35 days, I can look at my results. The app offers a nice summary of my monthly performance, so I’ll share my May results:

Daily average calorie intake: 1,518 kcal
Daily average exercise: 3,052
Daily average calorie deficit: 1,534
Total May calorie deficit: 47,545, which should equal 13.6 pounds lost
Actual weight loss (May 1: 214.0; June 1: 207.7): 6.3 pounds

So what does this tell me? It says that I am on the right track, and losing 1.5 pounds per week, roughly a 711 kcal/day deficit. So my workouts and food are actually only that far apart, not the 1,534 kcal deficit FatSecret suggests.

When I first started FatSecret (and working out and eating right), I did the math and saw that I had lost 10 pounds for a 35,000 kcal deficit, but now that my weight loss has slowed a bit (no doubt from a slightly smaller body as well), I think doing this math really helps my accuracy in setting and achieving my goals and keeps me from getting frustrated when the scale refuses to budge. Now I know why!

That also tells me that if I want to keep losing weight at this pace (and I think 1-2 pounds per week is reasonable and healthy), I need to keep striving for a deficit of 1500 kcal (based on FatSecret’s tracker), not the 1000 kcal deficit I would get by remaining sedentary and eating 1,800kcal per day.

So that’s my plan. I also reviewed this with my doctor and she agreed that eating 1,500 kcal per day would be reasonable and healthy for me as an RDI.

What do I eat? Everything, including some sweets. My macronutrient ratio (which I calculated based on 20 days of food logging) is 20% fat, 23% protein and 56% carbohydrate, or 63 g fat, 71 g protein and 172 g carbs on average. I’m pushing to reduce carbs and fat and increase protein, but I’m pretty close to where I want to be. I often make a green smoothie for lunch (spinach+lime+frozen fruit+whey protein) and my go-to foods are turkey, Greek yogurt, berries, wheat toast with peanut butter and roasted vegetables.

Thanks, FatSecret buddies for all your love and support! I am confident I can reach my goal!
Very Happy
I am not losing weight. I am gaining health. Since April 24, 2012:

Joined: Nov 11
Posts: 805

Posted: 01 Jun 2012, 12:37
Awesome post, Heidi!! Sounds like you've got your journey mapped out! I love it - hope lots of newbies (and not-so-newbies) read this and get some good, reasonable ideas from it.

Someone who is busier than you is working out right now.
There will come a day when you can no longer do this. Today is not that day.

Joined: May 12
Posts: 22

Posted: 01 Jun 2012, 12:59
THANK YOU! I am at the same place as you. I was wondering about the calculations as well.

Joined: Jan 12
Posts: 48

Posted: 01 Jun 2012, 12:59
I can't begin to tell you how much I LOVE this post. I am all about putting everything down on paper. This evening I will be going through the month of May and figuring out the same things that you have laid out here. I am excited. Math on a Friday night... thrilling stuff! I will do this all with a glass of wine in my hand Smile

Joined: Oct 11
Posts: 6

Posted: 01 Jun 2012, 13:08
this is such a great post because i really think most RDI calculators mislead people into consuming more calories than they ought to have in one day. it's great that you have really analyzed your weight loss and adjusted it for yourself.

Joined: Dec 10
Posts: 669

Posted: 01 Jun 2012, 13:12
This thread highlights why a one-size-fits-all online estimate of calories burned is unhelpful. There's far too much individual variability to make the estimates reliable, and taking the fatsecret estimates as gospel is asking for headaches.

There's a simpler way. Find a sensible starting point. It could be the fatsecret RDI. Or the Katch-McArdle formula. Or just multiplying your bodyweight by 12. Or purchase a BodyBugg.

However you get to your starting estimate, eat that many calories per day for 2 to 3 weeks. If you don't lose weight, subtract a few hundred calories (or more if you're actually gaining mass). If you lose too much weight, add a few hundred.
Fine-tune as needed. No exercise logging involved.


Joined: Apr 12
Posts: 49

Posted: 01 Jun 2012, 13:36
Hi Heidijoy, thanks for sharing.

I think that you are on track! Calculating RDI can be confusing. My understanding of the FatSecret RDI is that it already includes some activity. I set my activity level at low active because I work a desk job, however my afternoons/evenings are spent cooking and cleaning up after the family so I don't go as low as sedentary. I usually don't sit down until about 10:00 at night.

My assumption is that this activity is already figured into my RDI. So the FatSecret RDI of 2300 (i weighed 255 when I calculated) includes whatever calories I burn in my normal household activities. I lower my goal personally to about 2000 a day because I would like to lose 2lbs a week not 1 and if I keep it under a little in combination with exercise I figure that will balance out to about a 7,000 calorie a week deficit or 2 lbs lost!

I only log additional walking, weight training, or the other day I logged moving furniture and boxes because I did that for over 2 hours and that is not in my normal range of activity.

In the end we are both doing the same thing just in different ways Smile In your example you lowered your RDI and counted more activity. In my example I raised my RDI, but didn't count some activity...It all comes down to results. IF it works for you THAT is what you should do. I personally like logging my exercise. It makes me feel good. Keep up the great work and hopefully you have helped someone find a better RDI for themselves.

Joined: Feb 11
Posts: 1,218

Posted: 01 Jun 2012, 13:46
Definitely need to use caution with the RDI and calories burned.
I have a body media fit that tells me how many calories I burn. I'm 5'0" and in the 130s (lbs) and 37 y/o. My daily caloric burn ranges from 2200 on a low activity day (on my feet part of the day and 30 minutes of low intensity exercise) to a high of 2600 (on my feet all day w/ 60-90 minutes of intense exercise like zumba). I burn more on the weekends as I am busy running around and doing housework and such. I get about 12,000 to 16,000 steps in an average day - always over 10,000. I am on my feet during the week, but usually only for 1/2 of my work day and then when I get home I probably spend an hour on the couch.
I feel like I am fairly active and muscular, but not excessively so. That is just to give you an idea about RDI and calories burned. I aim for 1000 calorie deficit daily and usually average that. I lose just over 1 lb. per week, but some weeks I don't lose that much, while others I lose more - fluid balance, hormones, TOM as I am a female!!!

Joined: Apr 10
Posts: 107

Posted: 01 Jun 2012, 14:09
Excelling information sharing! Thanks! I always have feared the inaccuracy of the calories burned on exercise, as well as in the food diaries. Like you I analyze the heck out of it. Generally if I am losing and have a routine I can live with, I am happy. The fluctuations and plateaus always throw me for a loop, still!

Joined: Apr 12
Posts: 78

Posted: 01 Jun 2012, 14:59
Great advice. I know it couldn't come at a better time for me.

As a supplement to what you've said, I would suggest people who are doing exercise that is trackable on GPS, such as walking or riding a bike, get an exercise tracker to track their performance rather than relying on their best guess as to how much impact their workouts are having.

I am nearly 300 lbs, but I started walking for exercise several months ago. I've been using a tracker to stay motivated. But when I calculated my RDI, I completely overestimated the impact my exercise was having. Without counting the exercise, my calorie intake for the month of May suggested that I should have lost 2 lbs this month, I am up by 3 lbs since I starting weighing regularly.

I knew I wasn't working out like an Olympic athlete, but I did think I could describe myself as Low Active. It turns out the speed and distance I have worked months to achieve are about as much as normal weight people would accomplish if they were dragging themselves around with a head cold. Because I set my RDI based on a perceived workout level rather than an independently verified workout level, I ate, on average, 300 more calories per day than I needed in the month of May.

Many people complain that the trackers on this site are skewed, but in my experience, it is the perceptions of the user that are skewed.

It would seem that dieting is not for cowards. To be successful at this, you have to leave the little white lies you tell yourself at the door.

Joined: Mar 11
Posts: 1,279

Posted: 01 Jun 2012, 15:10
Why haven't I ever thought to check the whole month's daily averages before? Great idea! It's nice to see such an in depth explaination of how you're losing, that's so helpful to others who are in the same boat. We are all different and don't all lose at the same rate with the same exercise and RDI, so the one size fits all RDI calculators don't help all of us. Thanks for sharing!!
Goals for 2014:
Complete Couch to 5K- DONE!!!
Sign up for and complete a 5K- DONE!! 35 mins.
Plan at least 3 outings with the family that involve being active- 2 done

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