(I’ve written this from a cycling perspective, but I think the basic idea – going from a carb-optimized metabolism to a fat-optimized one – has a broader application).

For those who don’t know me, I’m a fairly typical recreational cyclist; in season I’m riding 3 times a week, generally anywhere from 75 miles to 120 miles, with a few goal events (I tend toward hilly events, such as RAMROD, Passport 2 Pain, and my very own Sufferin’ Summits).

Over the years, I’ve mostly used a low-fat diet; one focusing on low-GI carbs (brown rice, whole-wheat bread, etc.) for my normal diet, and one with high-GI carbs before, during, and after my rides.

That has worked okay, more or less, with a few issues:

I also had a related problem. I ski and teach skiing during the winter, which means that I have no weekend time for rides from December through mid-March, and a lot of chance to snack after skiing. Those combined with my work snacking, and in early 2016 I was at 178 lbs, about 6 lbs above my traditional adult weight of 172 lbs.

Some of you may be saying, “that’s not that heavy for an athlete”, and that’s true, but I did not like the trend.

I read a book on nutrition that had been sitting on my Amazon wish list for a year (reference below), I asked a few cyclists at my company about their experience with a lower carb approach. And I did a lot of research about nutrition and metabolism in general; if you want to talk about insulin, glucagon, ketosis, I can go on for quite a while, and I can also talk a bit about the current state of clinical measurements (HDL, LDL, LDL-P) and their relation to cardiovascular disease.  Oh, and the experience of indigenous people such as the Inuit and what happened when they started to eat a western diet.

My conclusion was that I was eating quite a few carbs in my diet and not much fat, which meant that my body was going to be optimized towards using carbs as a fuel source. My other conclusion was that eating the carbs was contributing to my snacking, because a) the insulin response to the carbs would tend to drop my blood sugar back down and b) the lack of fat wasn’t making me feel satisfied after a meal.

So, it was time to experiment. I’m not somebody who likes to make giant changes in my diet all at once, so I focused on lunch, especially at work. Here’s what I was eating before:

Monday: Burrito day. A whole wheat burrito, black beans, rice, chicken breast, cheese, guac
Tuesday: A half sandwich; chicken/turkey breast, cheese, lettuce, tomatoes, pickles, mustard
Wednesday: See Tuesday
Thursday: Taco salad day. In a tortilla bowl, black beans, rice, chicken breast, lettuce, guac, olives, cheddar cheese
Friday: See Tuesday

Just writing that, wow, that’s a lot of carbs. And wow, my cafeteria is boring.

Here’s what I switched to:

Monday: Mexican day. Black beans, half chicken & half pork, onions, lettuce, cheese, guac
Tuesday: “Barbecue day”. Either brisket or a half chicken with cole slaw, and a tiny square of cornbread
Wednesday: Salad. Greens + tomatoes, cucumbers, peas, kidney beans, red bell pepper, sugar peas, olives, mozarella balls, eggs, and chicken thight. All topped with an oil/balsamic vinegar dressing.
Thursday: Mexican day repeat
Friday: Salad repeat

Gone are tortillas, bread, rice. Added in are more vegetables, and considerably more fat (pork, brisket/whole chicken, chicken thighs, salad dressing)

The change was surprisingly easy, with the hardest part being changing my perception of fat. And I noticed an immediate effect on how I felt at work; I was less tired in the afternoon and I stopped snacking totally (it did help that the snacks moved out of my room).

I switched out my sugar-based hydration drink with an electrolyte one (Nuun has bothered my stomach and I don’t like plain water on rides, so I’m using Hammer’s right now), and went on a few rides.

And hated it. I means, seriously hated it. I was not running out of energy per se, nor did I have much hunger, I just could not put out any power to save my life. I played around with food with different levels of carbs before and during (I still think a carb recovery drink makes a lot of sense after a long ride), and it has gotten better but I don’t think I have that part figured out yet. More about that later.

That was working well, so attacked my breakfast next, which was a bowl of granola with fruit. I added an egg (sometimes two) in the morning and reduced the granola, and that’s where I am right now. I honestly probably need a bit more fat in the morning but it is so hard to change ingrained habits. I also changed my dinner patterns a little, trying to focus more on the protein/fats and the vegetables and less on the carbs. Also still a work in progress.

Oh, and for snacks at home, I’m eating cheese, home-made jerky (time to make a new batch…), and a fair bit of nuts. I’ll have some popcorn now and then, and maybe some chips.

One thing to stress is that, with the exception of paying attention to my snacking habits at work – where I have a “drink a glass of something first before you eat” rule – I’ve put pretty much zero effort into limiting my portion sizes. I just eat what seems decent, and stop when I am done.

Results:

My expectations weren’t very high; I would be happy if I got down to my usual weight and felt a little better on the bike.

What happened is that in about 3.5 months, I lost a full 10 pounds of weight, clocking in at 168 lbs this week. My summer shorts fit nice and loose, and today I pulled on a pair of 501s that I hadn’t worn for about 9 months, and they fit fine.

On the bike, I’m feeling strong but I feel like I might be missing a bit of my top end. On the other hand, last week I took 33 seconds off of my PR on a 7 minute climb and some of my riding friends say I’m faster, so maybe it’s not as big as I think, or maybe it’s just different. I have definitely felt less tired after a few hours on the bike, and my stomach is much happier on the bike.

References:

For a lot of reasons, low-carb is still fairly controversial and a number of sources say that its not healthy and you’ll grow a third arm or something. Much of that is due to the evolution of thought around the role of cholesterol levels in the blood, from “cholesterol = horrible” to “HDL / LDL” to “hey maybe LDL as a measure doesn’t work, how about LDL-P”. Remember that dietary guidelines have a *huge* lag time behind current research, and there is lots of out of date advice out there.

If you read anything, read a copy of “Why we get fat” by Gary Taubes. He may not have the whole story from a biochemical standpoint, but his overall presentation is very good. If you like lots of details, read his “Good Calories, Bad Calories“, but be prepared to bone up on your biochemistry.

Joe Friel – author of many training books for endurance athletes – has written some very interesting blog posts about low carb. In “Aging – My Race Weight“, he details an experience very similar to mine. Read “Becoming a better fat burner“. And read the comments on these posts as well.

If you are looking for research into low carb and performance, there is a decent summary here. Note that most of the investigation has been purely around performance, and the results seem pretty clear that low carb does not increase performance and may take a bit off the top end (perhaps in some people, perhaps in all). What the studies miss are the things that I really care about; if I don’t have to eat as much on the ride, I avoid the stomach issues that I’ve had over the years, I (hope) that I will have less trouble with low energy during the ride, and the obvious performance advantages of less weight.

If you want more details and/or references, please let me know in the comments.