Like all the best spiritual leaders, this diet theologian will leave you trembling

Eat. Nourish. Glow., the healthy eating book currently number one in at least three Amazon categories, came to my attention recently while I was in a stew of self-loathing over an out-of-control cake habit. Realising the time was ripe for a new regime, the feature in The Times spoke to me instantly. One Amelia Freer, pictured smiling and trim-wasted amid strawberries, was advocating a new approach to eating.

I had thought, as an armchair nutritionist and sometime dieter since my early teens, that I’d seen every new way of eating under the sun. Especially in recent years, as the mantra of ‘good fats’ has come to drown out all others (apart, of course, from fat-shunning, fruit-courting Weight Watchers, which still enjoys market domination). Could this blue smocked, fresh-faced Freer be offering new hope, even to those of us who know full well the peril of sugar and carbs but have still managed to fall foul of diets composed of avocados and macadamias? I instantly downloaded the e-book onto my ipad.

Freer does offer something a little bit special. Fear and loathing, and passion. This is food theology served up by a particularly enthusiastic evangelist. Eaten her way, food would save the body and therefore the soul. Eaten any other way, particularly the way of 'the 80s dieter' (the saddoes who know 'everything about calories but nothing about nutrition'), it kills. Like the best spiritual leaders, she left me trembling in fright. When would the pernicious, even deadly effects of the sugar in the slice of my boyfriend’s birthday cake kick in? How would the violent 'roller coaster' brought about by cereal consumption affect the shameless ignoramuses that I breakfasted with that weekend? I watched them closely, nervously awaiting a glycemic incident, perhaps a violent outburst, or a mid-Sunday walk collapse. Mystifyingly, none of these occurred.

Freer has many enemies in the food world, among them yogurt ('We have been grossly misled to believe that yogurts are a healthy product). But carbs, sugar and gluten are the worst. She tells her personal journey; a salvation story in two parts, then and now, divided by epiphany.

“'Back then I just ate for convenience… I used to arrive home, exhausted (not because of the [busy job as PA to the Prince of Wales] but because of my terrible diet) and couldn’t be bothered to cook so I would have cheese on toast or a plate of pasta with a glass of wine while slumped in front of the TV... I felt rubbish, but day in and day out, I made exactly the same food choices without any further thought... I felt exhausted all the time. Literally, all the time… I also suffered from terrible irritable bowel syndrome…'

And on and on the ailments go: her 'tummy looked and felt like it had a football stuffed inside it' and her skin would 'break out'. In short: 'I was a mess!' Eventually she seeks council in a wise priest - a nutritionist - and becomes an acolyte. The rest is a history of non-bloat and good skin. And lots and lots of money.

What also comes through here quite apart from the morality tale about sugar is the morality tale about what happens to people who eat out with too gay abandon (when she went out with friends, there was often ‘pasta, bread, desserts and drinking wine’ – imagine). And about those who indulge in that scourge of modernity at night: TV. For Freer, there’s only one position carb-munchers adopt in front of the box: 'slumped'. This from a woman who calls stomachs 'tummies'.

To someone who has grown up in the diet paradigm, it’s always rung a bum note when thin people say, as Freer does, 'I’m never on a diet. I just learned how to eat in a way that makes me feel and look better, which I then passed on to my clients'. This is clearly undermined by the preceding section that -  in true religious renunciatory language - insists that readers 'give one thing up' and then another. Leaving no dairy, no gluten, no sugar, basically no fun. Her diet is Lent, all the time. Which is what the new food theology looks like, unless you happen to have access to a permanent stash of coconuts, avocados and shredded courgette - and the time, of course, to render them edible.

Zoe Strimpel is a journalist and dating scholar, currently working on a PhD thesis at Sussex about the late 20th century history of dating