Cycling 80 to 100 miles a day, every day, for seven weeks is simply mind numbing. Chronic fatigue, aching legs, arms and backs are coupled with a brain turned into mush by too many towns and too many miles in too little time.

But riding Los Angeles to Boston this year, over 3,415 miles, was also a life affirming experience, and the culmination of a life changing one for me. In 2006 I could only ride a bike 200 yards, after battling with obesity for years. A gastric band helped me lose 77kg, but limited what I could eat. So, a fortnight before the ride began I had it relaxed. I had grown fearful of food – how could I now cope with eating the 6,000 calories a day needed to complete the ride?

Food remained a challenge throughout. When you fail to eat enough, you're compromising your ability to recover, as well as increasing your risk of getting sick. What I learned is that you eat today for what you're planning on cycling tomorrow. It also means pre-loading energy stores with hearty breakfasts before big rides, so you stand a better chance of mitigating the energy depletion from each day.

Being still heavy at 95kg – I was once more than 170kg – the climbing was particularly tough. Road gradients were never much more than 6% but some climbs across the Rockies could last 15 miles. In all, I climbed 28,000m.

My daughter, Catherine, 22, a keen cyclist, joined me for the entire ride. Being 30 years younger than me meant I was always chasing her. It was not a race but she always won.

There were other challenges. The heat in the Mojave desert in the first few days felt like riding in an oven. I was drinking four litres of fluid every 25 miles, and couldn't have got through without vehicle support.

Early on I got nasty hand blisters, followed by numbness from constant vibration, which made changing gears difficult. An early change was to replace my bike's racing saddle with a lovely Brooks leather saddle, so at least I was saved from saddle sores.

After about 2,500 miles my Scott CR1 team road bike began showing the strain, needing new tyres, a new rear wheel – this time I went for 32 spoke instead of 16 – a major gear overhaul and new shifter. It was a supported trip with Crossroads, who provided a great mechanic, planned the accommodation and route and carried our bags. There were even stops every 30 or so miles with, snacks, gels and fluid.

We rode on paper direction sheets and odometers, and invariably did not get lost. No real need for GPS. Every evening there was a US map on an easel at our hotel, put there as much to inform people what we were doing as mark our progress. At first it was disappointing when the black line on the map only inched forward for our day's work. It finally revealed a trail of pride.

The USA was full of surprises. Rude drivers in Missouri and Massachusetts who would prefer to push cyclists off the road versus friendly truck drivers in Arizona who passed giving a thumbs-up. The mega-long trains in New Mexico would toot their horns at us.

I was tearful at a few points: going over my first big mountain pass, crossing the Continental Divide and finally riding into Boston. I plan to return to ride it again in 10 years' time – at the very least it's a target to help keep my weight down.

• Chris Oliver is a consultant orthopaedic trauma surgeon in Edinburgh, and chairman of the Cyclists' Touring Club for Scotland. He tweets as @cyclingsurgeon