This documentary is recommended viewing for every personal trainer in London or further afield for that matter. Dr Xand van Tulleken, dietitian Hala El Shafie, and chef Stacie Steward reviewed a range of diets and weight loss methods in a light-hearted and entertaining way.
There were three categories of diet (10 day crasher’s diets, 6 week shapeshifter’s diets, and 4 month lifechanger’s diets) with two diets in each category. I recommend my personal training clients in London to avoid like the plague any of the crashers diets or the shapeshifters diets, and to treat the lifechanger diets with scepticism.
Crasher Diet 1: The Cleansing Diet
This involved drinking a mixture of water, maple syrup, lemon juice, and a tip of a teaspoon of cayenne pepper. You’re meant to drink a glass of this brew between 6 and 12 times a day.
I had a personal training client in west London who had tried a diet like this before I met her, and she said it left her feeling irritable, lacking in energy, prone to headaches, and totally ineffective in the long term as all the weight she lost in those 10 days piled on again as soon as she stopped. The diet also left her physically weaker.
Crasher Diet 2: All You Can Eat Fruit & Veg Diet
As it says, you can eat as much fruit and/or veg as you like. This is such an utterly insane diet, that I expect it is popular among celebrities. You are left malnourished in protein, a vital food group for growth and repair of your body.
Huge quantities of fruit are insane for a weight loss diet, as the liver metabolizes most of this fruit into body-fat. I had a client in Holland Park who gorged on fruit before I first met him, and he was over 22 stone in weight. He had read somewhere that fruit is a great way to lose weight.
Shapeshifter Diet 1: Bullet Proof Diet
You start the day with a special coffee with 2 tablespoons of butter. This diet is the creation of Dave Asprey, who clearly knows that the crazier the diet, the more commercially successful it will be. You’re not allowed any solid food until 2pm, or after 8pm.
Not eating after 8pm is ok, but not eating before 2pm is just insane and counterproductive.
Shapeshifter Diet 2: Alkaline Diet
You must stick to alkaline foods (80% of your intake must be alkaline), so no alcohol or coffee or tea. Also no red meat, which cuts out the single best source of iron and one of the best sources of a range of B vitamins. At least there are no crazy time restrictions on eating in the morning.
Foods you are encouraged to eat are vegetables, avocados, brown rice, fish. This is the least damaging of all the diets reviewed in the documentary.
Life-Changer Diet 1: Fasting Diet, the 5:2 Diet
This means eat just 500 cals (600 for men) a day on two days per week, and eat healthily the other 5. An example of your fasting day meal would be asparagus, 1 poached egg, and smoked salmon, but that would be your only meal on your fasting day.
Life-Changer Diet 2: Time Restricted Feeding Diet
On this diet, you must eat within a 10 hour time restricted window, such as 10am-8pm, and not eat anything (or drink anything with calories) outside those times. You must also stick to those same times every day. It’s designed to stop you snacking in the evenings.
Dr Xand van Tulleken then tested a range of weight-loss methods:
He took a pill called Alli, an orlistat pill which restricts your ability to absorb fat. This totally misses the point of healthy eating on every conceivable level. As a personal trainer I’ve warned clients off these pills again and again.
Weight Loss Hypnosis and Virtual Gastric Band
This is designed to tap your subconscious mind and program it with a desire to eat small portions. Dietitian Ursula Philpot thought this was an expensive method with only short term results.
The danger of weight loss hypnosis is that it over-emphasises small portions, often too small, which swings too far in the opposite direction. Smaller portions are only healthy up to a point, then it becomes malnutrition. And it’s the content of those portions which is relevant, not just the size.
It’s a shame that the “success” of each diet was measured simply in weight lost, without finding out how much of that weight was body-fat, and how much was water, glycogen stores, and muscle mass.
Dominic Londesborough is a personal trainer in London who offers his clients nutrition advice on an ongoing basis at no extra charge.