Weight Loss Fallacies: 2lbs per week and 1200 calories per day

I received an email the other day that sums up how popular diet/fitness misinformation can leave people frustrated, upset, angry and eventually to flat out give up on the idea of getting in shape.

So the email went something like this:

“I just read your book and it says my RMR is approx 1250 calories. I want to lose 2lbs per week because that is supposed to be a realistic weight loss goal…but to do that you say you have to create a 1000 calorie deficit each day, that means I can only eat 250 calories per day…but I also heard that you should never eat below 1200 calories per day…so how is this possible?!”

What is a realistic weight loss goal?

Of course I’m paraphrasing and this is not the exact words, but this is a very typical email I get every week.

There are a few different flaws and fallacies in this statement…did you notice them? If not, I’ll show you.

Fallacy #1. There is no scientific proof that 2lbs per week of weight loss is a safe or realistic goal that all adults humans can or should expect to achieve. This is a claim based on FTC advertising standards. You only hear this number because marketers aren’t allowed to say any more by law. If they could the number would likely be 10lbs per week. That doesn’t make it any more or less correct, because neither number is based on scientific evidence.

A 6’5 260lbs man can easily expect to lose up to even 4lbs per week, however a 5’1 woman is hardly in the same position. Instead of setting a weight loss goal based on poundage (ie: 1lbs, 2lbs, 3lbs per week) you should be looking at it as a percentage of your bodyweight.

A 6’0 tall man who weights 220lbs with a RMR of approximately 2000 cals/day could easily create a 1000 calorie deficit each day by cutting his calories to 1500/day and burning an additional 500 calories in a good hard workout (mix of weights and cardio).

1500 is still plenty of calories to feel relatively satisfied while still creating a fair sized deficit to facilitate a significant weekly weight loss.

Also 2lbs of weight loss represents less than 1% of his total bodyweight.

Now change the person to a 5’1 woman with an RMR of 1250 calories. She would have to eat around 750 calories per day as well as burning off an additional 500 in the gym. This is starting to sound more like torture than a reasonable diet plan.

The fallacy is that 2lbs is a good target for all body sizes…it is not. Smaller people have smaller metabolisms and shouldn’t expect to lose as much total weight as a bigger person. It would be more realistic for her to shoot for 1lbs of weight loss which would only require a 500 calorie daily deficit…this could be achieved with a much more reasonably daily calorie intake around 1000 calories with a 250 calorie burn from a workout. Doesn’t that sound much more realistic?!

Fallacy #2: 1200 calories is the minimum you should eat in a day

I don’t know where this number comes from and I will be spending some time in the near future looking it up. However based on the RDI and RDA for nutrients the actual lower limit for calories (when you add up the individual recommendations for protein, carbs and fats) comes out to around 800 calories per day for women and 900 for men. So even according to the RDA you can easily eat well below 1200 and get your daily requirements of protein carbs and fats.

These two false assumptions are leading many people down a path of frustration and weight loss failure.

Setting realistic weight loss goals is the first step to success.

Letting go of your fear of eating less food is the second step.

Once you realize it’s ok to eat a bit less food then you will start to see things really change.


  • Zaide

    Yes there is an RDA for carbs in the broad sense that 5 portions of fruits and vegetables per day are recommended, as are 4-6 portions of wholegrain/slow release carbs as part of a healthy balanced diet. As opposed to a carb phobic diets popular with lo-carb dieters today. Carbs keep most of the world alive. Most people in the world are not able to afford to live solely on high quality protein, low carb nutrient dense foods and good fats. Carbs are generally recommended.

  • Al Dalesandro

    RMR isn’t based on height alone, but by the combination of weight, height and age. So, for example, a 25 year old female, 99.5 lbs, and 5’1″ tall, would have a BMR of approximately 1253. She shouldn’t be trying to lose weight anyway as this is underweight. But if you insist, she could cut 250 calories off her diet and burn 250 doing a little cardio. Now, if she was 200 lbs, then obviously her BMR would be much higher (~1700).

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  • superbadkitty

    Great points, John. I am 5’3″ and have always found the minimum 1200 calories bizarre. The reason it is bizarre is I have never lost weight on all those calories and find it difficult to have 1200 calories everyday without putting on weight. My most successful weight loss periods were those where I was only getting between 500-700 calories per day AND working out 5 to 6 days per week at the gym doing at least 30 mins intense cardio (crosstrainer) plus an extra 30 mins walking on the treadmill. 3 days out of these 5 to 6 days, I would spend 30 to 45 min (mainly weight training) with a personal trainer. I was always in excellent health and felt great despite having well below 1200 calories. So sad to read comments on so many sites where people say they are having “the minimum” 1200 calories and are exercising but yet they can’t lose weight. And worse, some sites which actually tell people to INCREASE their calories (?!). About time someone looks at weight loss logically instead of parroting off each other! Thanks, John.