Slow metabolism – any 5:2 success stories to share?

This topic contains 8 replies, has 3 voices, and was last updated by simcoeluv 9 years ago.

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thundermonkey

4:44 am
28 Nov 15
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I have been having good success with 5:2 (3 weeks in, about 3 pounds off) and was wondering whether it would help a friend with a very different metabolism.

She has a very slow metabolism – although the TDEE calculator estimates she needs 2300 calories/day, she has found that she gains weight on 1600, and has to drop to 1200 in order to lose at a pound a week. (For 99% of human history this would have worked out great for her, but now…)

Since she maintains on 1400 calories a day, she is understandably resistant to the idea of adding 2 fasting days a week.

Has anybody out there been in her position, and had success with 5:2?

Pot-bellied Heron

8:40 am
28 Nov 15
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I would, without being rude, always question the infamous ‘slow metabolism’ as being the cause of anyone’s weight gain.

Unless your friend has a specific medical disorder affecting basal metabolic rate then they simply need to eat less, move more or both.

simcoeluv

7:29 pm
28 Nov 15
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Hi thunder:

It seems clear that your friend has a problem with calorie counting, not metabolism. The numbers you gave make no sense.

You state she loses a pound a week eating 1200 calories. To lose a pound a week one needs to cut about 3500 calories out of the diet, or around 500 per day. That would put her TDEE at around 1700. If she gains at 1600, well, with a TDEE of 1700 that would be hard. If her TDEE really is 1400, to lose a pound a week she would have to cut 3500 cal. a week, or 500 a day, which would mean she would have to eat 900 per day to lose a pound a week – but she says she loses a pound a week at 1200.

Perhaps she should do some real, accurate calorie counting for a couple of weeks. She may find she is eating more than she thinks, and in any event she will have some better ‘numbers’ to work from. Metabolism is metabolism, and you have to live with it. She appears to be able to lose weight at some number, so she just needs to know what her real TDEE is so she can make informed decisions on how she wants to keep below it.

thundermonkey

5:07 am
29 Nov 15
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Thanks for the comments.

simcoeluv, I mentioned that she lost 1 lb/week on 1200 calories/day. She was logging all her calories because she was participating in a weight loss study, and this number is an accurate one.

The other numbers are less so. I asked her at what rate she gained and she estimated 1600, and from that I interpolated a TDEE of 1400. I can easily believe that your value of 1700 is more accurate for her TDEE.

Still, 1700 is quite a bit lower than 2300, which this website’s calculator estimates for her TDEE. From this I conclude that she has a slower metabolism than normal[1]. This makes losing weight on a standard diet difficult because 1200 calories is not a lot of food, and limiting herself to that leaves her hungry all the time.

So I’ll restate my question:

For those of you with a slow metabolism (i.e. a TDEE significantly lower than normal), how did you approach the 5:2 diet, and did you encounter better success than you did with a standard diet?

[1]Her lower TDEE is consistent with normal human variation. The 2014 paper, “Examining variations of resting metabolic rate of adults: a public health perspective”, concludes: “No single value for Resting Metabolic Rate (RMR) is appropriate for all adults. Adhering to the nearly universally accepted MET convention may lead to the overestimation of the RMR of approximately 10% for men and almost 15% for women and be as high as 20%-30% for some demographic and anthropometric combinations.” The paper can be read at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535334/.

simcoeluv

6:04 am
29 Nov 15
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Hi thunder:

There is nothing unusual about your friend’s TDEE. There are many people on this site with TDEEs that are lower.

The only important number is the known one. What that means is that if your friend knows they can lose a pound a week eating 1200 calories then they can easily figure out if they want to lose weight using 5:2 or any other diet.

8400 cal. a week lets them lose a pound. On 5:2, they would eat 500 cal. twice a week (for a thousand total). That would leave 7400 for the remaining five days, or 1480 per day. If they want to eat more, they can and lose less than a pound a week.

Otherwise, they can go on any other diet and try to eat 1200 a day 7 days a week.

Their choice.

thundermonkey

2:39 pm
29 Nov 15
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simcoeluv,

Thanks, your comment is very helpful. One last query and we are done here – can you direct me to any success or non-success stories from these low-TDEE posters that you know about?

simcoeluv

6:16 pm
29 Nov 15
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Hi thunder:

Success stories are all over this site. The maintenance thread is full of them. What most people don’t realize when they start any diet is that their TDEE falls as they lose weight. That means that many that stick with their diet and are successful find losing that final ‘5 or 10 pounds’ is very hard. That is because the TDEE of a normal weight, say 5’4″ woman is only about 1500 (I know there are many variables), and when they get close to their goal weight they find they have to ‘eat almost nothing’ to lose those final pounds and it takes a long time, too. The human body is incredibly efficient and needs very few calories to operate – especially when compared to the number of calories an overweight person us used to eating.

That is why ‘blaming’ being overweight or not losing weight as fast as one would like on having a ‘slow metabolism’ means little – the TDEE of ‘normal’ weight people is by definition very low.

Better to focus on eating less to lose weight – because that is all it takes – and not saying ‘it can’t be done’ because of a ‘slow metabolism’. Any diet will cause weight loss if it has few enough calories, it is just a matter of picking one you can stick with.

Good Luck!

thundermonkey

5:27 am
30 Nov 15
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simcoeluv,

Your comments are on point, and I think I can infer from them the answer to my original question.

What I was really wondering, which got obscured by my framing it poorly, is whether the 5:2 has any impact on weight loss outside of caloric issues.

Dr. Mosley took up the diet in order to lower his IGF-1 levels, after all. (He got a nice reduction after 5 weeks, unfortunately that is a single data point.) The weight loss was a secondary consideration.

The 5:2 diet seems guaranteed to deliver some loss since it reduces weekly calories consumption by 20%. However, by timing calorie consumption the way the 5:2 does, you are (hopefully) also triggering healthy changes in the body independent of any weight loss. I was wondering whether these changes make the diet more effective, or less effective, for losing weight relative to diets where the calorie consumption is not timed.

From what you are saying people on the forum are not reporting any such effect, and you can predict weight loss from 5:2 purely from calorie counting and a knowledge of your TDEE. That’s useful to know.

simcoeluv

6:33 am
30 Nov 15
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Hi thunder:

I have posted the ‘history’ of 5:2 on my thread – it was an ‘accidental’ diet. At this time, it is clear 5:2 is a safe and effective weight loss diet. I am aware of no studies that show it is more – as you say, one data point is not proof of anything. Several posters have indicated they have had their IGF-1 levels checked at their start of 5:2, but none that I am aware of have come back with ‘results’. The one clinical study that looked at IGF-1 levels with a 5:2 type diet indicated they increased. There is nothing else inherent to IF that would cause weight loss over and above simple calorie reduction.

But for most people, that is more than enough. The nature of the diet makes it easier for many to follow.