For me, VLC doesn't work with my running. Also, my performance starts to suffer if i skip meals. With endurance sports, calorie counting works best for me to lose weight but it's important to take a long-term approach with a small calorie deficit so it doesn't hurt performance. You might check out Cordain and Friel's Paleo Diet for athletes. Also, I've had success with Matt Fitzgerald's Racing Weight books. Though those are not paleo, I make them paleo by substituting his grain recommendations with sweet potatoes or other starches.

Lean gains is pretty dam tough for competitive athletes. I wouldn't suggest that to him. Also he's most likely not going to build much if any muscle unless he's doing some sort of resistance work.

As suggested by one of the posters above me. A high carb paleo diet would benifit him. He can try high carb low fat on training days. High fat low carbs on off days.

I don't think you should keep throwing paleo diet at him though. Better to lead by example & let him customise it as he please. Rob wolf has a good write up about this.

I like Lindsay's post. A potentially useful site is called paleoista.com. It is run by Nell Stephenson and she is a paleo endurance athlete heavily influenced by Cordain.

As an athlete, Cordain's Paleo for Athletes works really well. Essentially, eat regular paleo with a special focus on carbs in the pre- and post-workout meals. I tried low-carb during the season, and, even when I was hitting my calorie needs, I felt drained far more than normal.

Mark Sisson (and others) maintain that, properly trained, an athlete can train and compete on a fat-prominent diet. There is a 2-3 week period to retrain the body to prefer fat stores to glycogen stores, after which normal performance levels should return. Personally, I'm a bit skeptical, as many of his recommendations are more geared to the casual aesthete than the competitive athlete, but it may be worth further investigation.

Have him get a newleaf assessment and use fitday to track calories. With a Polar FT60 watch or http://www.polarusa.com/us-en/products/maximize_performance/running_multisport/RCX5 (splurge and or triathlete).

This works for my cycle friends.

They will however tell him eat anything which we know better...

Focus on meat, eggs and green leafy vegetables and then a bunch of carbs around workouts over an hour long...

Have him do burpees as an exercise that will challenge but not create bulk. Make sure he sleeps alot. Early to bed and early to rise. The cycling is going to spike cortisol and sleep helps lower cortisol. Early to bed help keep grehlin levels low.

My concern is generally less with the type of exercise and more with the frequency. Hitting hard every day is simply exhausting, if nothing else the stimulating effect of carbs may be necessary to keep going. I don't know that it's actually necessary though - the energy and speed are always there, it's just a question of how I feel. If I overload on carbs though after exercise then it can seriously disrupt recovery.

Depending on his current situation with regards to competition, I'd say it's really worth trying training rides on different strategies or even fasted. Paleo certainly, you can still have honey and fruit if you want. I'd recommend trying not to rely on it and eating plenty of steak and eggs for breakfast before deciding if he wants to play with rice and potatoes. One of the biggest mistakes I think people make is switching food sources while trying to restrict quantity. Always better to make sure you're eating enough for what you want to do, then once you've adjusted to the new lifestyle you can fiddle with it to lose weight if necessary. Do it right and skipping a meal will probably be no big deal.