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5/24/13 10:46 P

1. There is no way 1500 calories a day is enough for someone your size.

2. 50g of carbs is a pretty low number. I have heard of people getting the "carb flu" when first reducing carbs as the body adjusts to making glucose through the process of gluconeogenesis, so that might be what's happening here.

I eat 2000 calories a day with about 100g of those coming from carbs. I'm 5'4" and 122lbs.

LADYSTARWIND SparkPoints: (83,977)
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5/24/13 10:42 P

MYRICAERR: Woo Hoo to you on the biking!! Way to Go!!! Also on joining Spark Welcome to the Journey to get healthy....!

I admire you for being willing to ask intelligent ,thought out questions, and I hope what these folks have told you make sense.... It certainly does to me.

As I also bike ride, I have one little piece that might apply no matter what sort of "diet" you are trying to follow. You didn't indicate: when you are eating.... About 30 min before your trip home, are you making sure to have a healthy snack?? I find it especially helpful when I am biking to have something beforehand, and if I am riding more than hour, I stop at about 45 min and have something more. (For me, generally about 15g Carb with fat/Protein--I happen to like Zone bars, but anything will do!) Along with lots of water, (or diluted PowerAde) throughout my ride. If I don't, I basically do what you did: "hit the wall" or "bonk" or ...lots of names for it.... Take care, and Happy Biking! You are doing great!!

MOTIVATED@LAST Posts: 15,451
5/24/13 9:41 P

No, it sounds to me like your glcogen reserves have been pretty much depleted.

The body can convert fat to energy only slowly. But the body holds glycogen reserves of about 2000 calories, which is normally more than enough to cope with the demands of exercise, and then replenish them later.

The brain is the biggest calorie burner in the body at about 600/day. Carbs are the preferred source of fuel for the brain, although in a pinch it can break down protein for what it needs. However, the brain cannot run on fat. And the body will sacrifice nearly everything else to keep the brain supplied with what it needs.

Carbs have about 4 calories per gram, so your 50g is about 200 calories worth. Your brain likely has been depleting your reserves to get what it needs. Combined with a fair bit of exercise, your glycogen reserves have run down to the point of empty, and bascially your body could only supply as much energy to your muscles as it could convert from fat (as noted above, this is a fairly slow process). Say a glycogen deficit of around 400 calories a day (add back what it has converted from protein, subtract glycogen burned during exercise) - I'm not surprised it has taken about a week to get to this point.

I'm not necessarily against low carbs (although I would single out simple carbs as being of greatest concern, rather than all carbs being the enemy), but 50 g is TOO low.

Quite apart from the low carb thing, I am guessing that you are burning around 500 calories a day with your cycling (very rough guess) - 1500 calories overall may not be enough to support this level of activity. Even at 1500, 40% carbs (which is the bottom end of most nutritionist's recommendations) would have you at 600 calories/150 grams.


PS. On re-reading, this all sounds like I am yelling at you - you have asked a genuine question, and don't deserve being yelled at. It's really intended to put a bit of math and a framework around what you need to eat to support yourself.

NOBLEEQUESTRIAN SparkPoints: (5,640)
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5/24/13 9:18 P

When I used to eat low carbs I was tired all the time. It's why I no longer use a low-carb diet and strongly advise against it.

You seem to already understand that low carbs=low energy and you probably already know that fats and proteins can be converted into energy (I'm guessing you've upped your protein intake?) so let me explain a bit more:

Carbs are a quick source of energy. Proteins, while capable of being converted into energy, take a lot of energy to simply do the conversions. Not only this, but if you don't get in LOTS of extra protein your body will not have enough protein to be converted into energy.

Lack of carbs generally means your not eating a lot of fruit, which is a large source of vitamins and water. If your not getting in enough water you WILL feel fatigued. To make matters worse, A LOT of water is needed to break up proteins. One of the reasons why low-carb diets are known to cause quick weight loss is because they are also eating high amounts of protein, and thus requiring a lot of water, causing water loss in your body (it's a temporary effect, which is why many low-carb dieters gain back a lot of weight after a few weeks or months).

If I were you I'd stay away from the low-carb diets. It is possible to be healthy on a low-carb diet but its VERY difficult and is not a worthy lifestyle to follow.

DRAGONCHILDE SparkPoints: (61,458)
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5/24/13 9:16 P

When you're doing any kind of intense exercise, low carb is likely not a good choice. Why? Carbs are your body's preferred fuel, and you've already experienced why. Your body's telling you there's a problem... LISTEN to what it has to say. Try adding more complex carbs into your diet, and see what it does.

May I ask why you switched to low carb, even when unconvinced of its benefits? What was your motivation?

How much are you burning week-to-week, and what does your current diet look like? "50g carbs" doesn't tell us much... wh at kind is just as (if not moreso) important than the amounts. If you'd consider creating a public sparkpage and sharing your nutrition/fitness trackers, we can offer more advice.

MYRICAERR SparkPoints: (3)
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5/24/13 8:56 P

This is my first time posting and I don't know if I'm doing this right so please feel free to ignore me or yell at me if not...

I had a pretty bad experience on my bike ride home today, and I was wondering if anyone has ever experienced the same kind of thing, and if you have, if you have any advice?

So about a month ago I went from an almost sedentary lifestyle to riding my bike to and from work every day, which is about a 16 km round trip. I'm 5'10'' and 228lb, so for someone of my size and fitness level, this isn't an easy change. I'm usually pretty tired by the end. Sometimes on the hills my legs seriously burn. But I always get through it and feel awesome. It's been getting easier every day.

Now, about a week ago, I started a low carb diet. I've been eating less than 50 g of carbs a day. And I'll be honest, I've read a ton of research about carbs and protein and insulin and all that, and I'm not entirely convinced that low carb is a great idea, but nonetheless, I knew I needed a change so I decided to give it a try. I'm eating about 1500 calories a day.

So I started this diet. And today, on day 5 of the diet, on my bike ride home, I found that I had absolutely no energy on my bike ride home. My legs were just unable to pedal. I had to get off the bike and walk for a while every few blocks. It was raining and cold and for a while I honestly didn't know if I was going to make it home.

I'm guessing that this was because my glycogen stores have been completely depleted because of the diet. It also may have had to do with the rain, since this was the first day I biked in the rain. But mostly I just had no energy at all, and it was pretty scary.

So... has anyone else had problems with exercise when starting low carb diets? Did your body eventually adjust and start getting energy from fat instead, or did you have to add more carbs to your diet in order to maintain your activity levels?

Basically, what I'm asking is should I hold out on my diet and wait for my body to adjust, or should I take this as my body's way of telling me I need to eat more carbs? Or should I be worried that the lack of strength was for a different reason altogether?

Thanks in advance...

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