In September 2015, Huel posted an advert offering to pay a person £35,000 ($49,000 / €44,000) to live only on its nutritional powder for one year. Of course, the UK company was inundated with applications from all over the world, but no one was suitable and the trial was postponed.

Made from milled foods such as pea and rice protein, flaxseed and oats, you simply add Huel to water, mix and drink it. While the company doesn’t suggest users live on its product solely, the trial was intended to prove that you could, and through a diligent diet, exercise and regular blood work, back-up its health claims.

“We have had some problems. We had a lot of applicants for this trial and a lot of people making very persuasive arguments for why they think they’re the right person, then, when we start dealing with them and ask them to start doing stuff, they pull out,” says Huel co-founder Julian Hearn.

“It’s a huge commitment and there’s got to be a huge amount of trust.”

Although initially seen as ‘easy money’, the candidates couldn’t overcome the reality of the 12-month period, particularly the impact on social occasions; there could be no indulging at birthdays, weddings or holidays, and absolutely no alcohol.

After speaking to Hearn about the benefits of Huel, and two nutritionists who disapprove of powder supplement diets in general, I decided to test it myself to find out why it was such a challenge.

The mathematics of meals

Before tasting a drop, I had to work out exactly how much Huel would get me through the day. I used a calorie counter to calculate exactly how many calories I need for my size and age, worked out how many grams of powder that made, and divided it into meals.

From the very start it felt like the attitude towards food was different – this was precision fuelling

All the weighing and counting made me feel a bit like an old-fashioned dieter, but I’m not the best at maths and was wary of accidentally gaining weight. From the very start it felt like it required a different attitude towards food. This was precision fuelling.

Hearn recommends that new users gradually replace meals over several days, so I planned to replace breakfast, then also lunch for two more days allowing for a 500 calorie evening meal, before finally foregoing all foods and drinks.

I normally have coffee and a cereal bar for breakfast and work though a soup/salad/sandwich option as a desk lunch, so switching to a shake didn’t seem hard. In fact, it meant eating more calorie-wise, but less bulk.

When I opened the powder pack it was sweet and creamy-smelling, and I could see some reassuring grains. The taste was a mildly sweet, inoffensive vanilla that was neutral enough not to repulse or tempt you into bingeing. It took me a few attempts to get a good consistency, but I settled on a light, thin 1.5 scoops for breakfast and a thick three-scoop lunch.

It was certainly practical – dusty – and filling, but in the first few days I was still keen to get home to eat. I was amazed at how far I could stretch 500 calories and how good it tasted when it was my only regular food. On day three I hit a huge slump and decided to delay replacing my evening meal. I felt tired, a little faint and achy. It was hard to focus on work and I kept making silly mistakes.

I was prepared for teething problems with such a big diet change and it was only early days, so I spoke to Anthony Nguyen, who had previously switched to a Soylent diet, to get some advice. He said that going 100% and drawing it out rather than guzzling it down often helps.

“When I have it, I sip it over time and by the time I get to the bottom I feel sufficiently satiated and don’t feel the need to eat more or snack,” he explained.

Is variety the spice of life?

Day four was fantastic. I was over the hump, refreshed from sleep and felt surprisingly energised. After breakfast I wasn’t counting down the minutes to lunch and had no rumbling stomach or cravings. I felt much better on 100% Huel and found that it actually helped level-out my energy, as the portions were more evenly spread out.

However, a new issue popped up as I quickly became fixated on other people’s food. Drinking my functional cold shakes in a busy office, I was hyper-aware of all the beautiful food aromas around me. Flavoursome curries, pastas, chillies and burritos – heaven scent!

The company has a very active website forum so I went there to see how others were coping, and picked up several recipes. Huel is essentially flour, so I tried changing it up and cooking with it.

First I added the company’s strawberry food flavouring, which was quite strong, and it was a welcome change. I also blended coffee into my breakfast shake, and added baking powder to a thick mixture to make American-style pancakes. This assuaged the boredom but, as the base is vanilla, I was craving something savoury so tried a not-entirely-unsuccessful oatmeal recipe using rich mushroom stock instead of water.

Clearly, I was missing the variety that comes from different temperatures, textures, flavours and cuisines. It became harder to plough through and when my colleague said, “why are you still doing this?” I decided that I’d had enough.

Freedom of choice

Before starting the trial, I spoke to nutritionist Mark Bennett at Entire Wellbeing who said that, “as a species we have evolved to get our nutrients from eating real food, not from supplementation.” This made a lot of sense in terms of how our eating habits have developed. I felt full and fine from Huel, but was strongly drawn to the various smells of fat, salt and sugar because they’re fast tracks to energy. Also, as no single food provides every nutrient, we instinctively seek variety, for health as well as pleasure.

“One of the problems with these types of diets is that they don’t teach people how to eat a healthy and varied diet,” said nutrition scientist Helena Gibson-Moore at the British Nutrition Foundation, also siding against powdered foods. “Establishing healthy eating patterns is important for good health and for maintaining a healthy weight…and many people find them hard to maintain.”

Yes, it doesn’t teach you how best to manage foods, but I found that physically weighing out and seeing what constitutes a balanced diet made me think about how I feed my body. On an average day I choose a meal according to how hungry I am or what I ‘fancy’, but never what I need. It seems far more logical to treat food as fuel, adjusting intake to maintain optimum health and energy, as opposed to arbitrarily eating. And Huel offers a pragmatic solution.

Replacing all food and drink seems unrealistic in the long-term, and sticking to it was certainly tough for me (it was less than two weeks before I started dreaming of cheeseburgers!) and all those who dropped out of the one-year trial where even a large sum of money wasn’t motivation enough. But it works for some, such as Nguyen, Hearn and Hearn’s customers.

“The best use case I hear is that people use it to replace the convenience meals that people go and grab – a sandwich, or a panini or a McDonalds or something like that,” says Hearn. “We see it as being a flexible tool.”