I’m skeptical of this new (to me) recommendation of 100-120 grams of sugar/hour for a 9-hour ride. Even if you’ve trained your gut to handle that much sugar for that long, the long-term impact on your health can’t be good. It’s not surprising your body was looking for something else.
The first and last time I tried to eat that much sugar for that long was a 13-hour MTB ride - and I never ate another PowerGel or drank another drop of Cytomax again. 
The craving for “proper food” could actually be salt cravings. That was very clear to me on my recent 600 km when it was 30C and I suddenly thought “I want a bowl of broth and I want it now!!” Lack of salt/electrolytes is less obvious in the body than running out of fuel but for me a craving for savoury food is an indicator.
I’m not so worried about long term health impact, since I have a very healthy diet off bike.
Also, I rarely do rides of this distance.
More worried about performance when I do decide to do them.
I wonder if performance is better by adding something other than sugar for these long rides. What do pros do when the car is giving them food?
There is no shortage of supremely fit endurance athletes with Metabolic Syndrome from excess sugar consumption, which is the source of my skepticism. A few years ago, it was a hot topic in the CO endurance scene when some local heroes were diagnosed. The key takeaway is that low body fat and great fitness don’t make us immune to such things.
Pros have always mixed in some real food with their on-bike sugar during lower-intensity parts of the race. Allen Lim’s famous rice cakes (which are delicious) are one example. Small bread rolls with low-fat meat and jam, energy bars, be as creative as you want. A little protein and a little fat go a long way as long as the pace allows you to chew and will improve overall performance in long days.
Is metabolic syndrome caused by eating too much sugar during exercise? Mayo clinic didn’t mention it in their summary or in how to prevent it:
A lifelong commitment to a healthy lifestyle may prevent the conditions that cause metabolic syndrome. A healthy lifestyle includes:
It would be great to see studies that look at long term effects of eating carbs as we do on a bike.
I know endurance athletes typically live longer, but correlation doesn’t imply causation. Maybe they’re endurance athletes because they have a higher general health/energy level/genetic code which also means they’ll live longer (IE they’d live longer even if they never took up sports).
@Dr_Alex_Harrison has some information on this I know. Supposedly during exercise the body handles the carbs differently, IE the muscles are using all of that sugar in the bloodstream as fuel, therefore less insulin is released to get the body back to baseline.
In any case, I think there are a lot of variables out there.
Regarding other foods during these long efforts, I wonder if there is a general guideline? Rice cakes are still just carbs, but what about fats and proteins? Where is it beneficial to add them during an effort?
Well, Lim’s rice cakes include liquid aminos and bacon and eggs, so not exactly all carbs.
It’s only strictly beneficial to consume protein and fat beyond 2-3 hours, and only in small amounts. Remember this is for ultra events where you pace at tempo or below, and your body uses fat, amino acids, and carbs for fuel. The protein in your on-bike food is meant to prevent your body from taking what it needs from muscle tissue.
For shorter, high-intensity events or on sections like climbs when you’re pinned don’t want anything but carbs.
Agreed on the other variables re: metabolic syndrome. I’m not making any specific claims, just noting a risk factor.
Sure they did - insulin resistance = too many carbs, generally speaking. Weight gain is just one of the possible symptoms.
I Imagine it’s highly individual and probably dependent on what you’ve trained/practised to some extent, but for me 5-6 hours seems to be the ‘break point’ where I’m happier with some solids in the mix. Not necessarily something super heavy, but breaking up the gels/drinks more frequently with small amounts of something more ‘substantial’ like a bar seems to strike a good balance without being much more challenging logistically.
Salt has definitely helped in my experience too- but mostly I’m just not very good with sugar on an empty stomach lol.
There is no insulin spike while taking on sugar during exercise. We need to differentiate between metabolic syndrome causation from on the bike nutrition vs off the bike. Generally endurance athletes consume lots of sugar in both scenarios
Experiment! Definitely individual. When I’ve done hard century rides with tempo IFs, those have been supported by 60g per hour of Gu Roctane plus another 30+ grams/hour of carbs from food. I absolutely respond better when eating food, so I practice eating real food on the bike and not guzzling 90+ g/hour sugar water.
Sir you’re a machine! 155miles is incredible and at 0.7 IF specifically. Respect 
