Book Review: “The Obesity Epidemic: What Caused It? How Can We Stop It?” by Zoe Harcombe

Zoe Harcombe is one of those nutrition writers who I find myself agreeing strongly with in some areas, and strongly disagreeing in others. Her degree is in maths and economics (Cambridge University) so she’s clearly intelligent, but not degree-educated in nutrition. She does however hold diplomas in Diet & Nutrition, and Clinical Weight Management. Here’s a brief summary of some of her main arguments, together with my perspective as a personal trainer, based on my 10 years experience of training overweight clients in London.

The main cause of obesity

Zoe Harcombe is adamant that Western governments’ demonisation of dietary fat, and failure to recognise the dangers of processed carbohydrates, particularly sucrose and high fructose corn syrup, is the main cause of the ten-fold rise in UK obesity between 1980 – 1999. Back in 1980, 2- 3% of the population was obese, by the turn of this century it was 25%. That’s a staggering increase. Her central argument is that we are eating too much processed food, and not enough real whole food in its natural state. I agree that processed carbs and sugar are a major part of the problem, but there are other major factors such as alcohol consumption, lack of exercise, and saturated fat consumption which also play a major part.

The food industry

Zoe Harcombe condemns the junk-food and processed food industry for its major contribution to our obesity epidemic. Her key message is that we should avoid processed food (ready-meals, junk-food, fizzy sugary drinks, cakes, biscuits, bread, indeed all processed foods), and stick to natural wholesome unadulterated food.

Saturated fat

Zoe Harcombe is surprisingly relaxed about saturated fat consumption, and says it’s fine to eat as much red meat as you like. “No research has ever properly proved that eating saturated fat is associated with heart disease, let alone that it causes it,” she says. I’m dubious about this statement. There is strong evidence from many scientific studies that high levels of saturated fat are linked to heart disease, and certain types of cancer too. It is an inescapable fact that an increase in saturated fat in your diet leads to an increase in body fat, unless you are exercising at such a high rate that all the fat is being burned as energy, as in the case of Arctic explorers. Zoe’s defence of red meat is valid to some extent. Red meat is high in protein, and particularly high in the mineral iron, and in a form that is readily absorbed and utilised by the body. However, you can get just as much (and as easily absorbed) iron from liver, which is low in saturated fat. In her defence, she does list liver as one of the top 5 foods she thinks public health authorities should promote.

Fruit and Vegetables, and the “5 a Day” health message

As a personal trainer, I was taught to encourage my clients to eat plenty of fruit and veg, at least 5 portions a day. I quickly learnt that this “5 a day” message is far too blunt and vague, as one of my earliest personal training clients, a man in his 50’s in West London (Holland Park to be exact), interpreted this advice as “eat as much fruit as you like”. I discovered what he was doing after the first week of training him, when I read the food diary I’d asked him to keep. I think the message should be “eat no more than 3 portions of fruit a day, one of them an orange, and eat 4-6 portions of vegetables a day, mainly green leafy vegetables such as broccoli and spinach and spring greens.” It’s not as catchy or memorable as “5 a day” but it is far better advice. Zoe Harcombe is far more scathing of the “5 a day” message than me, far too scathing in my view. She focuses heavily on the fact that the “5 a day” advice started out as a marketing campaign by the fruit and veg companies, implying that the underlying motive was industry profit not public health. She is strongly against fruit, because of its high levels of fructose (fruit sugar) which can only be metabolized by the liver, and any excess turns to body fat. I agree that fructose is a hidden danger (in the sense that most ordinary people do not recognize its effects on unhealthy weight-gain), but two or three portions  a day are safe in my view, as long as you make one of those portions an orange for the vitamin C content. Where I disagree is her blanket criticism of vegetables as being an inferior source of vitamins and minerals, when compared to red meat and eggs. This is a far too simplistic approach. Yes, it’s true that red meat is a better source of iron than spinach or any other vegetable, but vegetables are a great source of other vitamins and minerals. My biggest disagreement lies in Zoe’s demonisation of dietary fibre found in vegetables. Soluble fibre is vital for reducing our levels of bad cholesterol in the blood, and insoluble fibre is vital for colon health and reduces the risk of bowel cancer. Zoe’s view is that fibre inhibits the absorbtion of micronutrients, a claim I’ve yet to be convinced of. “The biggest tragedy is all the lost opportunity of this misguided 5 a day campaign,” says Zoe. She thinks that the health and weight of our nation would have benefited more if all the “5 a day” marketing money had been spent promoting the following 5 foods: liver (all vitamins, many minerals), sardines (vitamin D and calcium), eggs (all round superfood with vitamins A, B, D, E, K, and minerals iron, zinc, and calcium), sunflower seeds (vitamin E, minerals zinc and magnesium), and dark green veg (vitamins C, K, and the mineral iron). Again I agree that all the foods she mentions should be a major part of our diet, and note that she promotes dark green veg as one of her top 5 foods, after demonizing vegetables elsewhere in the book for being inferior sources of micro-nutrients and too high in fibre. Zoe Harcombe completely ignores the value of phytochemicals in vegetables, the range of plant-based chemicals which have many health benefits.


Zoe Harcombe is right to condemn processed carbs, but she over-plays her anti-carb message. We need complex carbs for the slow-release energy they provide, and I advise my personal training clients to eat sweet potato, quinoa, bulgar wheat, and oats. But Zoe veers too far towards the Atkins philosophy of demonising all carbohydrates, without making the vital distinction between processed vs unprocessed, and simple vs complex carbs. In her defence, she does allow a small portion of brown rice in her prescribed diets, but this is not enough.


Zoe Harcombe rightly debunks the myth that dietary cholesterol is bad for you (citing Ancel Keys’ groundbreaking research in the 1950’s) , but goes on to make the error of claiming that there’s nothing wrong with saturated fat. It’s dietary saturated fat that raises your LDL (bad) blood cholesterol levels, but Zoe Harcombe claims there’s nothing wrong with it. It’s true that dietary cholesterol, such as that found in eggs, does not lead to higher blood cholesterol, so I agree with that element, and agree that we should all eat plenty of eggs. They really are a power-house of nutrients. Just make sure you buy free range.

Live natural yoghurt

Zoe Harcombe is a strong advocate of live natural yoghurt, and here I’m in complete agreement. The live cultures support a healthy gut flora (the friendly bacteria in your colon) which helps the digestive process, and the elimination of bad bacteria and other toxins such as candida.


A major element of Zoe Harcombe’s thinking on the obesity crisis is that we can’t exercise our way out of it. I agree to the extent that exercise alone is not enough, you need healthy eating too. But  as a personal trainer I know first hand from all my London clients that exercise has many health benefits, and is a vital part of tacking obesity, together with good diet. But Zoe goes further in her criticism of structured exercise (eg- the gym, running, exercise classes, as opposed to what she calls ‘natural exercise’ of ordinary daily activity) by saying in a forum on the World Cancer Research Fund website: “I cannot support attempts to overcome the obesity epidemic with exercise.” This is such a bizarre and sweeping statement that it deserves a separate blog post to deal with it. Look out for my next blog on the link between the obesity crisis and lack of exercise, and the role that exercise can play in helping to combat the obesity epidemic. Meanwhile, please contribute to the debate by leaving a comment below.


  • Dom says:

    Having re-read Zoe Harcombe’s analysis of the evidence on saturated fat, I have to concede that the evidence that saturated fat is harmful, is not as rigorous as I first thought. However, I’m still dubious about the message that you can eat as much saturated fat as you like without any harmful effects. Everything in moderation!

  • Dom says:

    Having re-read Zoe Harcombe’s analysis of the evidence on saturated fat, I have to concede that the evidence that saturated fat is harmful, is not as rigorous as I first thought. However, I’m still suspicious of the message that you can eat as much saturated fat as you like without any harmful effects. Everything in moderation!