Carbs – the good, the bad and the ugly

When is sugar okay

Different kinds of sugar

Sugar metabolism and absorption



Carbohydrates have gotten a pretty bad reputation in the last few years – a not entirely undeserved reputation – for the bad effects that it can have on you. What is often not appreciated is that role of carbohydrates in exercise. So, I thought I’d write a little something that (with any luck) will make the whole subject less confusing.

I’m also going to simplify a bunch of information. Let me know if I went too far.

Carbohydrates and blood sugar 

Your body has regulation mechanisms to keep your blood sugar level constant. When it gets low, you get hungry.

And then, presumably, you eat. Through a wonderful and intricate process, the food gets digested, and your blood sugar goes up. And now, the important part:

The way in which your blood sugar changes depends on what carbs you eat.

This is described in a very simplistic way by a measure known as the Glycemic Index. You determine this by giving a group of volunteers a small portion of different foods and measure how much their blood sugar goes up over a specific time.

And then you end up with a chart that gives a value for each food (well, actually, two values. There is one scale where glucose=100 and another where white bread=100).

Why does this matter? Well, if you eat high glycemic foods, you get a spike in your blood sugar, which your body tries to regulate down with the release of insulin which pulls the sugar out of your blood and stores it as fat. Unfortunately, the insulin response is too much, which causes your blood sugar to drop, which makes you hungry, so you eat again.

Over time, this is believed to lead to insulin resistance, where the body stops responding to the insulin and the blood sugar stays high. At that point, you have type 2 diabetes, or are close to it.

This effect has been immortalized in the “I ate chinese food, but an hour later I’m hungry again”. Chinese food is often eaten with a lot of white rice, which has a fairly high glycemic index.

But, it’s not as simple as all that. First of all, it’s not just the glycemic index that is important but the amount of carbs in the food you eat. Carrots have a very high glycemic index but don’t contain much carbohydrate so they have little effect. The glycemic index is also a function of the whole meal, not just one component, and fats and protein both have a moderating impact on the glycemic index of carbs.

Sugar in your diet

effects of all sugars, including fructose

Sugar Absorption & Conversion

The ultimate destination of carbs is glucose, which is either used directly in the brain (and muscles), or stored in the liver and muscles and glycogen.

But first, the carbohydrate needs to be converted to glucose.

 glycemic index drawbacks.





insulin response





50 nice miles, 30 bad ones…

On Saturday I went out to get some quality miles in preparation for Ramrod. Because I rode with my wife and daughter on the flying wheels 25 mile route, I didn’t get my usual century in, which means that the longest ride I’ve done this year is the 60 (ish) miles on the 7 hills 11 hills metric (ish). I felt great on that ride, but that’s far short of the 145 miles that I’ll be doing on Ramrod, and I really wanted some serious time to work on my pace and fuel strategy.

I elected to start with the FW 50 miler and add on from there. The first couple of hours was pretty nice – my strategy is to work to keep my HR below 130 BPM (higher is okay on big hills) and my cadence above 90 RPM. So, I slogged up Inglewood, flew up Ames lake, took a quick nature break in Carnation, and then rode to fall city and up fall city-issaquah.

At that point I felt pretty well, and descending back into Issaquah at 45MPH always makes me smile. But then it started to unravel.

First of all, my stomach (fueled on accelerade and a bagel) was a bit unsettled, and I seemed to be a bit dehydrated and down on salt. I had a bit of jerky which tasted great (and helped), but I’m reluctant to depend on my desire for salt because I’m a sodium-based snacker. Going through Issaquah, I went to sprint at a stoplight and manage to tweak my IT band on my right leg (I’ve been doing some PRK stretches, and I think that was contributory). Which was bad – it was twinging fairly significantly.

I had originally thought that I might climb the zoo, but decided instead to get over the hill on 164th, the easiest route. I rode very easy on my smallest gear (something like a 37/27), made it to the top, and stopped at Lewis Creek park for water and to stretch.

Which helped immensely. I descended the back side of the hill to coal creek, crossed, and then descended down and over 405. That series is probably my favorite one around – you lose 800′ on the trip from the top of Lakemont all the way down to the water, and there are few places where you need to brake.

I got on the trail, rode to Kirkland, and felt a little better up Market and up through Juanita, and then took the trail back home. But a few problems persisted:

1) My energy was really, really weird. I felt okay on the trail but had trouble keeping my speed down.

2) When I went to climb home (up 171st from W. Lake Sam), I was really out of oomph. I was clearly eating enough and had okay hydration, and my speed wasn’t that high, so I’m not sure what it was.

Anyway, checking the download on my polar, it was 80 in 5:10, which put me at about 15.5, pretty good considering how easy I rode the first 50. And I ended up with 3500 feet of vertical, more than I expected (164th added a bunch).

My analysis is that 1) The accelerade isn’t working on the longer distances and 2) I need more electrolytes. I bought some Perpetuem at Gregg’s (who inexplicably only had the unflavored), and some endurolytes, and the perpetuem worked well on my Tuesday night ride, though I had to cut it with half a scoop of accelerade to cover the weird flavor.

Older cycling posts…

The posts that I referenced in my comparative insanity all came from my work(ish) blog. You can find all the cycling posts listed here.

Progressive insanity…

Cycling is an exercise in progressive insanity. No matter where you’re at, there’s always somebody who’s just that little bit crazier than you are, no, not the total whackos that do things that are ridiculous, but just that next little step…

It all starts with riding an hour on the flattest roads that you have around, and finding that pretty challenging. And maybe one day, you ride for two hours, and it wipes you out, but you’re happy you did it.

And then meet somebody who is doing a charity ride, and you think “maybe I can ride 50 miles” at once – it’s pretty intimidating, but you ride some more, and then you finish it, and you’re happy, but dead.

The next year, you decide that you’ll do a century. This is a real milestone, and you can tell its a real milestone by the reaction of the people you mention it to. “In a day?” they say. And you do the century, but you’re slow, and while you finish, you don’t have a lot of fun.

The next year, you do a bit better in the century, and then you do a multi-day ride.

And then you start riding with a group – not a hardcore group, but a group that just likes to ride. You get a new bike – a fast one – and suddenly that century isn’t a goal event but a training ride on the way to a double. That two-hour ride that used to be a goal event is now the minimum – you don’t leave the house for less than two hours. And you start adding hills to your rides *on purpose*. You even start up a website devoted to hills.

You start looking for the hilly organized rides. You do one, two, three, four, and in there you throw in a double century.

And then you decide that RAMROD looks like fun. It’s 143 miles with 10,000 feet of climbing.

A long time ago at my job, I met a co-worker who was into cycling, and he told me about RAMROD. I had driven the route that he rode, and I thought that he was absolutely bonkers.

And now, in three weeks, I will also be officially bonkers.

The scary part is that as I’ve progressed, I still know people who are just marginally more crazy than I am, and that makes me seriously worried.

You’re working too hard

I get the opportunity to see lots of new riders on our group rides, and there’s a common thread that shows up over and over.

Nearly everybody who is new is working out too hard, and many people are working out too much. What do I mean by this?

Well, to get better at cycling, you need to focus on both your anaerobic and aerobic systems. But the way you focus on these is totally different.

Your aerobic system training is best done at a fairly light intensity – one at which you can still talk comfortably. This is sometimes known as “base miles” or “LSD (Long Steady Distance)”. This sort of riding helps your body get better at getting oxygen to your muscles, better at using your stored flat, and (very importantly) builds up your muscles and ligaments to deal with increased loads. Pros and races put in 1000s of miles at these sort of intensities.

I think of this sort of riding as setting your baseline.

Once the baseline is set – which is a 6-8 week process (or more) – then you can add some intensity to the mix to work on the anaerobic system. This involves interval work – things like 1 minute all out, 1 minute recovery, repeated 6 times, or hill repeats, where you do the same hillclimb over and over. The details are a subject of another post, but these workouts increase your ability to produce power, and your ability to deal with short exertions and recover quickly. And they’re very small in quantity – you might only do 2 sets of 4 intervals in a workout.

This is also the time to add in tempo rides. Tempo rides are done right below around your lactate threshold (another big subject, but where your legs start to hurt when you’re out of breath is a decent starting point) and last from 15 minutes to perhaps 30 minutes. Tempo rides improve your ability to deal with lactic acid, so that you can ride at a higher heart rate but still staying aerobic.

What I see in beginning riders is working out as hard as they can for the whole ride. And that works fairly well when you start riding – frankly, pretty much anything works well when you start riding – but it has problems once you start to get some fitness. That pace is fast enough that there is a significant anaerobic component, which is much faster than optimal to train your aerobic system. And, even though it feels like you’re going really hard, you are riding too fast to be able to do your intervals all out.

So, if you want to get better, you need to get in the base miles, and then you need to have focused workouts of very high intensity with limited duration.

Helpful tips for travelling athletes…

Since I tried out the CTS Classic Training last year, I’m still on their email list.

Today, I got some helpful advice for athletes who travel to events.

  1. First, create a checklist of what you will need before, during, and after your event
  2. Second, do not wait to pack your bags
  3. Finallky, set aside a few important items for your carry-on, such as shoes, helmet, and pedals

Wow, what insightful tips those are. I never would have thought of creating a list, or packing my bags ahead of time.

I can add a few that I think might be more helpful:

  1. Go online and find your accomodations ahead of time. Print out a map, and if you have time, the location of grocery/convenience stores.
  2. Pre-pack items into gallon-sized ziploc bags so they’re already grouped. If you have stuff to put in your jersey pocket, put in all in one place so you don’t have to go searching.
  3. Don’t assume you can locate decent food and refreshements. Plan ahead


Climb4Cancer ’07 will be on August 4, 2007 benefiting the Lance Armstrong Foundation.

This goes up infamous Zoo Hill. Last time I rode the Zoo, I think I did it in about 27 minutes all the way to the top. The time trial will be “Zoo Light”, which is only about 1000′ of elevation gain in 2 miles. If I was in equivalent shape, I’d be expect around 20 minutes, but I’m hoping to do it in less time than that.

Last year’s winner did it in 11:34.