Some Thoughts on the BBC Horizon Programmes “What’s the Right Diet For You?”

I’ve always had a great deal of respect for the way the BBC addresses nutrition and diet in some of its programmes. In the past they have compared people’s progress on diets such as Atkins and low fat diets. And I’ve been a big fan of Horizon for many years, though lately the presentation seems trivialised and sensationalised.

Just recently there was a series of three Horizon programmes purportedly tailoring diets to the reasons why people are overweight. The series was highly promoted as ground breaking experiment and the biggest of its kind, so I really looked forward to it, particularly in view of the excellent programmes by Mosley for Horizon a couple of years or so ago.

Maybe I missed something, perhaps I should watch the programmes through again in case I have, but my initial impressions are:- Overall I was disappointed with the series of three, though I felt that some of the tests or demonstrations comparing the groups, or looking at how people respond to foods were very interesting, and more significant and applicable than the “right diet for you” comparisons.

What disturbed me was the lack of controls with these experiments, which turned the programmes into little more than ratings-grabbing showmanship. What a waste. I hope that behind the scenes some real science was done, even if it didn’t make it to the actual programmes. The experts obviously know their subject and I suspect it was the production of the programmes which turned it from a well-rounded experiment to a rather superficial presentation. Horizon is a shadow if its former self.

The basic idea behind the programmes is a sound one. People gain weight for different reasons, and unless those reasons are addressed, losing weight will be well-nigh on impossible. Horizon divided the people into three groups; emotional eaters; constant cravers and feasters. They also devised an online test so that viewers could assess themselves.

Emotional eaters are those who overeat when they are upset.

Constant cravers are always hungry, never satisfied. They have “hungry” genes

Feasters are those who once they start eating, they don’t stop. They tend to eat more than they need at mealtimes because the “full” signals from the gut are flawed or interfered with.

The BBC selected 25 people for each group from the many applicants. I presume, though they didn’t say so, that they matched them between groups so that as far as they could, they were comparing like with like. I suspect also that they selected people who showed a strong tendency for one reason, unclouded by the other two reasons. As soon as I heard the groupings I thought, “But I’m all three of those.” And quite a number in the 5:2 Facebook group felt the same, or when they did the online test got a result saying they were none of the above. However, if you’re wanting to compare groups you need to weed out those who might skew the results by having more than one reason for their overweight. But Horizon should have said so, because people may be misled or bewildered by thinking they are none of the above or all of the above from the rather crude, magazine-style questionnaire on the website.

Horizon gave each of the groups a diet purportedly tailored for their reasons for being overweight.

The Feasters were given a high protein low glycaemic index diet since protein promotes satiety whereas easily absorbed carbohydrate undermines satiety.

The Constant Cravers were given a two day modified fast diet where their intake was restricted to 800kcals for two consecutive days in a week, and they could eat ad lib the rest of the time, but healthy eating along Mediterranean lines.

The Emotional Eaters were given a traditional restricted calorie healthy eating diet with group support.

The first two make sense, but after the first programme I was worried that the emotional eaters had drawn the short straw with the diets. It didn’t seem very different from what has been trotted out as the answer to obesity over the last 50 years – you know, the diet which obviously hasn’t worked because sticking to it in the face of emotional upheavals is difficult. Any straying from the tight restrictions can then lead to low self-esteem (thoughts like, I’m greedy, I’m a pig, I’ve no self-control, I deserve to be fat/unhappy because I’m useless and everyone else is better at dieting than I am and I’ll always be fat so I might as well pig out on this chocolate because I’m miserable and I just can’t do this – type destructive thoughts and negative emotions). I didn’t think that group support alone would be sufficient to help this group, not long term, though having diet buddies can help – after all, what is the 5:2 Facebook group if it’s not a support group? I thought that unless the emotional side was addressed, the Emotional Eaters group was on a hiding to nothing. It wasn’t until the second programme that the BBC mentioned the group was offered additional support in the form of Cognitive Behaviour Therapy.

Before I go into my other reasons for disappointment in the programmes, I will mention something that caused me unease regarding the coverage of the emotional eaters. The programme singled out two ladies who had some traumatic childhood memories associated with food. My concern is that anyone who, using the self-analysis questionnaire, came out as an emotional eater, might now be looking for some childhood trauma that triggered their emotional eating – looking for something to blame. Something that might not be there. But emotional overeating doesn’t necessarily stem from childhood traumas associated with food. It’s far more likely, I think, to relate to our responses to stressful situations. It’s far more likely to be due to the way we handle stress, and that is due to the way our brains are wired during foetal development, and how our anxieties are dealt with during nurturing. But I’m not a psychologist, so what do I know?

It would have been far more useful to cover some strategies for dealing with stress. I suppose they did mention exercise, but that isn’t a strategy for dealing with full-on in the face stress at the time.

They did an interesting test where they sent some of the emotional eaters and some from the other group(s) out on a simulated driving test, a very stress-inducing situation. They showed that after the stressor, the emotional eaters were producing more of the stress hormone cortisol, and that they ate considerably more than the “control” group. That was interesting, but alas, it’s not that well controlled. I would like to have seen them compare all three groups’ eating before the stressor and afterwards. I would like to have seen them demonstrate that the emotional eaters ate more than they had previously. As it stands, all they showed was that the emotional eaters ate more than the control group, but that may or may not be due to the driving test – they could have eaten more as a group than the others just due to chance or just because they ate more normally. Poor controls, and rather disappointing. Perhaps they did do that but they certainly didn’t show it in their “ground breaking” TV programme.

Something that was better done was splitting the Feasters group into two, feeding one group on protein rich, low GI food, and the other group on carbohydrate laden, high GI, low protein food, and showing how the high GI carb meals left them unsatisfied and how they went on to eat more. But I would like to have seen them do the same experiments with the other two groups because I think we can all experience this, it’s just exaggerated in Feasters.

I also thought the experiment where they compared how constant cravers focus on food far more than the others was very interesting. With our obesogenic environment where food is not just available at every turn, but pushed at us with cleverly constructed, psychologically clever adverts, constant cravers have a very difficult time.

But my main frustration with the series stems from this: I would like to have seen how all of the groups responded to all of the experiments and all of the diets. As it is, what the BBC did was preselect people, and give them a diet which was aimed at addressing the reasons, then try to demonstrate why that diet was the right one for that group because of their subsequent demonstrations and experiments. That’s not good science.

What they should have done is compared how each group does on each diet. How would the emotional eaters have done on a high protein low GI diet? How would they fare on intermittent fasting? How would the other groups do on the other diets? We will never know because they were only tested each group with the one diet. They should have been tested on all the diets to see if the one designed for them was the best.

This would have been further complicated by the fact that when we start a diet there is a honeymoon period where we are losing weight and it’s not too hard. So to do a properly controlled experiment they would have had to start some cravers on the high protein diet, some cravers on the intermittent fasting diet, and some on the traditional diet with group therapy, and so on with each of the groups, then change the diet to another, and then to the third diet, and see how well each group did with each diet. And they should have done it blind. Obviously whilst this is more scientific it’s also a heck of a lot more complicated and expensive.

As it is, though, the programmes did not show that any one diet was the best for any one group, despite all their headlines and big talk. They just showed that each diet worked for each group for a short period of time. That’s disappointing because most people will lose weight on a diet at first. It’s the long term weight loss that matters. It’s disappointing because the programme purported to demonstrate exactly that – that a specific diet was right for a specific group. They did not show this.

There will be people now who have done the rather shallow questionnaire on the website who have decided they are one sort or another, who now feel they have to follow the diet purportedly (but not proven to be) best for that type of person. Based on bad science.

I noticed also that the BBC did not say which group had lost the most weight by the end of the three months. If these people were matched, then that would have been a very interesting observation, more so than the fact they had lost lots of weight. It might have been the most significant result. Maybe they didn’t want to tell us because maybe one group’s loss far outstripped the others.

The good thing about the programme was that it showed that we are overweight for different reasons and that one diet strategy does not fit all. It also showed how it is very difficult to stick with any diet, and that we should get away from this atmosphere of blameworthiness that goes with being overweight. Someone who is not a feaster or a constant craver will not be able to understand this drive to eat, when they themselves are satisfied and find it easy to stop. Someone who is not a stress-head will not understand the drive to eat high sugar high fat foods after a stressful experience. Hopefully this series will have shown the non-overweight person why. That is presuming that people who are not overweight actually watched the programme (I suspect not – why would they?)

Being overweight is not a positive lifestyle choice, it’s because our genes and psychological makeup can make fighting being overweight very hard, harder for some than others, especially in the face of cheap, instantly available processed foods and seductive advertising. That doesn’t mean that being overweight is unavoidable, but it does mean we have to move beyond the obvious reasons (too many calories in, too few calories out) and start addressing the underlying reasons specific to that person. The Horizon programmes were a big step in the right direction, but were wholly inadequate in addressing what is the “right diet” for us.

Unless the obesity epidemic is sorted, in a few years’ time the NHS will be unable to cope with all the obesity and metabolic syndrome related illnesses. Many people, especially newbies in Kate Harrison’s 5:2 Facebook group were very confused by the Horizon prgramme’s intermittent fasting diet for Constant Cravers. With 5:2, the limit of calories on fast days is 500kcals for females, 600kcals for men, or ¼ of their total daily energy expenditure, and the fast days can either be back to back or non-consecutive. In the Horizon Right Diet programmes (NOT the Mosley Horizon programmes) the intermittent fasting was 800kcals for two consecutive days and intended to induce ketosis. They are not quite the same but both are valid forms of fasting.

And does the Feasters’ result mean we should all be eating stacks of protein? Well, maybe not, because animal protein is associated with higher levels of IGF-1, a growth hormone associated with an increased risk of cancer [ref example]. Low GI is good, though, but that’s nothing new.

Despite being an “Emotional Eater” (but only just) I will be sticking with intermittent fasting, thank you. I see no benefits in the other diets the Horizon Right Diet programme presented per se. But there are tweaks we can do to make each intermittent fasting diet individual for us, those highlighted by the Horizon programmes. This approach is something I have been advocating over the last couple of years or so, without actually dividing people into rather contrived subsets. Most of us are not one specific type. We are a mixture. So to my mind, the default diet which we are most likely to stick with is intermittent fasting.

Our food choices with that way of eating could be tweaked such that, for example, if we know we can’t stop when we start eating, we know we should fill up with protein and low GI, and eat slowly (but bearing in mind the problem with protein). If we are a constant craver, then perhaps we need to avoid tempting places, or have some useful low calorie snack to distract us from the processed food snacks we end up being tempted by time and again. “I can eat that tomorrow” is a very handy concept. And if we are emotional eaters, then maybe we should be seeking some emotional support so that when something stressful happens that might derail us from any diet, including 5:2, we can deal with the stress effectively without abandoning our long term weight loss/weight maintenance strategy. And this, I fear, is where we are sadly lacking. Where do we find such help? Books on CBT? Counselling? Groups of diet buddies? This wasn’t made at all clear in the programmes.

One good thing with 5:2 is that because it’s intermittent, we get away from the “I’ve broken my diet I might as well give up” attitude. With 5:2, if a fast day doesn’t work, we can dust ourselves off, maybe ask ourselves why, try to address any issues, and do a fast tomorrow.

(For more on IGF-1 and protein, have a look at the work of Valter Longo and the work of Luigi Fontana.)

(For some  books on coping with emotions:



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5 responses to “Some Thoughts on the BBC Horizon Programmes “What’s the Right Diet For You?”

  1. Interesting.

    A couple of ideas: In some parts of the world: Asia, Latin America, and Africa food is more easily accessible than it is in the West. The difference is the type of food that is available. It is generally fresh, lots of fruits and veg, and unprocessed. In the West the problem is our food is mostly processed and not fresh.
    Now in these same areas, where Western-style processed food have been adopted, the same issues with weight and health are increasingly documented.
    I have an issue with the idea of “diets” and wouldn’t have watch the Horizon programmes for that reason. I suggest that changing our eating lifestyle should be emphasized more. Choosing what and how we eat as well as how we think about food is more important than the “diet” idea. I do know many people who’ve been successful at maintaining their health and weight on variations of a 5:2 type eating lifestyle.
    From reading your post, I am curious how the participants were chosen. If it was a self-assessment, was there any further follow up to confirm the assessment? I think I will take the online survey to see what category it determines I am. Will post the results and my opinion.

    • For my height I am in the overweight category (the peachy color); but I didn’t fit any of the diet categories.

    • I think the ultimate selection was based on more vigorous testing than the online questionnaire. I imagine they did not select people who did not fall well into a specific category.

      I agree about the fruit and veg situation. I remember someone proudly saying to me. “I love fresh veg, I eat them at least twice a…” I was expecting her to say “day” but instead she said… “week”!

      I also know someone whose F&V consumption is woefully inadequate but will she listen? 😦

      We also have the situation in the West where there are food deserts in poorer neighbourhoods simply because the big supermarkets won’t set up there and the people are too strapped for cash to travel.

      And for some reason we are forgetting how to cook. You’d think in these days of TV cookery shows and the internet everyone would be able to cook, but I sometimes think the cookery programmes make things too complicated with expensive ingredients that a lot of people can’t afford. It can be daunting.

  2. Well written, Linda. I am inclinedd to agree that Horizon is a shadow of it’s former self – ratings grabbing showmanship rather sums it up!

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