3100 kCal: Insane?

December 1, 2011 7:08 AM

I'm assuming that the RDI of 3100 calories from my Android App is a bit high, right? YNMD.

Today I decided to start tracking calories better for two reasons: in the past, I've tended to go overboard or underboard (feast or famine - literally!), and I'd rather eat healthy while knowing what I eat and eat moderately.

My goal is weight loss. I am a male. I weigh about 226 lbs and I'm 5 ft, 8 inches. When I plugged in my dimensions and weight loss goal, my Android app recommended a daily intake of 3100 calories.

My question is: What is an ideal caloric intake for my size to lose weight but not leave my body in starvation mode? Is it correct to assume that 3100 calories is very high for someone who has a goal of losing 50+ lbs in the next year or so?

I think this is insane because if I'm just following the 'golden ratio' (i.e. 45% calories from carbs, 25% calories from fat and 30% calories from protein) for their 3100 calories recommendation this comes out to: 362 grams of carbs, ~90 grams of fat and 225 grams of protein. Simply put, that's a lot.

posted by glaucon to health & fitness (9 answers total)

3100 calories is not a weight-loss regime unless your activities resemble those of a professional athlete. If the only info you gave the app was 226 lbs, 5'8" and no activity info, you need to either check the units (226kg is a lot! 5.8meters is a lot! this would throw stuff way off), or try a different app.
posted by aimedwander at 7:15 AM on December 1, 2011

According to this site your base metabolic rate (what you need to remain at your current weight) is around 2160. (yes, your mileage may vary,of course - this is an estimate) If you want to lose 50 lbs over the next year, you need to reduce your caloric intake or increase your activity by around 175,000 calories over that period, so your target should be 1600-1700 per day, plus any additional exercise.
posted by deadmessenger at 7:20 AM on December 1, 2011 [2 favorites]

I use MyFitnessPal for tracking calories on Android.

I plugged in your height and weight with a goal of 175 lbs. at a rate of losing 1 lb. per week. (I assumed a sedentary lifestyle, e.g. a desk job.). It suggests 1900 calories a day.

In general MyFitnessPal has worked really well for me. I would recommend giving it a try.
posted by oddman at 7:27 AM on December 1, 2011 [1 favorite]

All these things do is guess calorie needs based on some formula. The formulas used take into account different factors and depending which formula is used you can get wildly different values. I've seen various different formulas and calculators and they give my daily calorie needs as somewhere between 1500 - 4500 per day.

When I went to a professional dietician she used the Harris Benedict equation, which for you would put your maintenance calories at about 2600 + any exercise calories - subtract around 500 to lose on average 1lb a week (its not actually that simple but no need to go into that here). Obviously you would need to reassess your needs as you lose weight (a lot of people forget that). I don't know what formula your app is using but if that is the calories it told you for weight loss rather than maintenance, its either using a formula that comes out with a figure even bigger than any I've found or they're assuming you're very active - approx 1k calories burned per day through exercise.

deadmessenger, 2160 is the calories he would need if he lay in bed all day. Even sitting up would increase that.
posted by missmagenta at 7:40 AM on December 1, 2011

You're not breastfeeding, so yeah, it's insane.
posted by the young rope-rider at 8:15 AM on December 1, 2011

Deadmessenger is right. Also, please do yourself a favor and let go of the "starvation mode" myth. It's been widely refuted by many credible studies and diet companies including Weight Watchers. This damaging belief actually keeps a lot of people from losing weight because they erroneously think cutting the necessary amount of calories will instead keep them fat somehow (not true at all).

Your metabolic rate won't go down significantly (or at all, potentially) if you cut calories responsibly and lift weight/do resistance training a few days a week. You only truly go into "starvation mode" when your body fat hits the 5%-ish mark.
posted by devymetal at 8:25 AM on December 1, 2011 [3 favorites]

When I was actively lifting 3x a week, I lost fat at a rapid clip taking in 3600 kcal/day. In fact, that was the fastest I have ever lost fat. My intake was closer to 40/40/20 P/F/C ratio though. Without the lifting, or with a P/F/C ratio like you describe in your question, yeah, 3100 calories per day ain't gonna drop you any weight. Really, I guess the takeaway message here is that there are a lot of other things going on in fat loss besides kcal intake.

As an aside, I wouldn't recommend eating below 2000 kcal/day no matter what. If you are looking at this over a year, and plan to stick it out, 2000 kcal/day will absolutely drop the weight over that time frame.
posted by Sternmeyer at 8:27 AM on December 1, 2011 [1 favorite]

Also, keep in mind that the FDA allows food producers to be off by up to 20% on their calorie information as printed on the packaging, and there are some studies that indicate they tend to run 8-10% low pretty consistently; restaurant meals are even worse. (In other words, the companies are pretty good about measuring calories, but they appear to be lowballing the package figure, while just staying within the rules. See also: "zero calorie" Tic-Tacs.)

It's entirely possible for that ~10% to be the difference between weight loss and weight gain -- 10% underestimation of a 2000C/day diet is like eating an extra Krispy Kreme every morning.

Plus, different people process food with greater or lesser efficiency -- the calorie information on the box assumes a standard model that many people who want to lose weight may not fit. And unless you get it measured directly, the BMR estimates used by most tools have a fairly high error on them as well.

All in all, you basically have to pick a calorie / exercise goal, stick to it for a few weeks, see if you're losing weight, and tweak it upwards or downwards to achieve your desired rate of weight loss. You shouldn't treat it as a "set it and forget it" goal but as an iterative process, where you slowly figure out your true calorie target based on what inputs actually allow you to lose weight.
posted by Kadin2048 at 8:55 AM on December 1, 2011 [2 favorites]

Two rules of thumb, which I'm sure you could shoot a thousand holes in:
* 12 calories per pound per day to maintain your weight. For you, that's 2,712 calories.
* If you cut or exercise 500 calories per day, you'll lose one pound per week.

My guess is that exercising works better than strictly cutting calories. I wouldn't get caught up in all minutiae, studies and arguments on this topic. Keep it simple. If you cut 500 calories per day out of your diet and do 30 to 60 minutes of vigorous exercise every other day, you will lose weight.
posted by cnc at 9:58 AM on December 1, 2011