Diets have been making headlines again, but this time the news is a little different from usual. Instead of arguments about which is best the message is this: it doesn’t matter what diet you choose, just so long as you actually keep doing it.
It’s potentially good news, if you know how to choose right.
Obligatory comedic picture.
“Any Diet will do as long as you stick to it”
Research out last week in the Journal of the American Medical Association (1) was highlighted by a number of news outlets including the BBC . The paper looked at a bunch of named diets, Atkins, Ornish, Weight Watchers and so on to see how effective they were. The conclusion was that in terms of weight loss they all work, as long as you actually do them.
In fact this study is the latest in a line of studies (2,3,4) comparing various types of diet, high protein, low fat, low carb etc. The findings seem to suggest there’s a fairly small difference between diets that are shown to work. Remember we’re talking about the more mainstream stuff here, not the weird and wacky juice fasts etc.
The pendulum swings back of forth in nutrition, from the 80′s low fat fad it swung in the 90′s the other way to low carb, but the influence of the emerging science seems to be bringing the pendulum back towards the middle again. And possibly to rest? Time will tell.
Problems: Nutrition Science does it again.
***Feel free to skip this section if you’re not interested in the backgrounds to the studies***
The studies themselves are ‘meta studies’: studies of studies. They bring together existing research, by screening relevant papers, including the ones that meet their inclusion criteria (quality, size, structure etc) and then pool the results.
Meta studies are useful because in research the more data you have the better, and using meta studies you’re able to bring smaller studies together to form a larger – and possibly more significant and reliable – conclusions.
If you get the process right.
The studies comparing diets in the past have suffered from a few pretty annoying problems, that leave many in the nutrition community scratching their head.
An obvious one is that they were comparing diets of different calorie intake (3). This is an annoying and pretty basic flaw. Clearly some diets cause you to eat less and that’s why they work, but by ignoring calories you can’t compare the efficacy of for example ‘low fat’ vs ‘low carb’ on a like for like basis.
Another issue is researchers selecting and compiling the data for studies being a little over generous with the definitions of ‘low carb’ or ‘low fat’. The major issue is there’s no agreed definition in nutrition science for these terms. And – like a dieter saying “of just one more square of chocolate” – there’s always the urge to make the amounts as generous as possible so you can include more studies and/or more data. The result is that you get ‘low carb’ and ‘low fat’ results included that just aren’t ‘low’. (2,4), and a similar issue exists with the high protein diets.
Then of course there’s the other perennial problem, the people doing the diets just won’t do what they’re told. If there is one thing this body of research proves it’s that the more extreme the diet the harder it is to stick to.
Diets: What actually counts?
The final sentence in the conclusions of the latest research, taken from the abstract is the most significant:
“This supports the practice of recommending any diet that a patient will adhere to in order to lose weight”
What this really means is that you’re best choosing any sensible diet that suits your life. Take your pick, but choose wisely. As I discussed in a bonus section to the book, many diets work, the important thing is choosing the one that works for you. Perhaps though you think this all sounds a bit soft, and you can grind through on will power and hard work for 12 weeks on your ‘hardcore’ diet.
Well, you’re wrong, or at best short sighted.
Here’s the crux of the matter. No matter how good the results, go back to old behaviours and you’ll get the same results. Most people will want the results long term. Long term results mean long term changes. Goodbye hardcore, hello sustainable.
Usually in the real world losing fat and keeping it off means a big effort at the beginning and smaller more sustainable changes long term. In order for this to happen you have to choose the diet style the best suits you and this depends upon a number of things:
- Food preferences – what you actually like eating, or at least things you don’t dislike.
- Lifestyle – activity levels etc
- Access to particular foods – option around work etc
- Cooking skills
Those are the make or break factors, these are the things you should concentrate on, not on which is best Atkins or Ornish. Some factors you can change, others you can only tweak or work around, but this is where the effort should be concentrated. This is one reason I like fasting for many people, a few sustainable but concentrated bursts of effort that can then – used right – trigger subtle but lasting changes in the rest of the diet.
References, Links and Further reading
1) Johnston, Bradley C., et al. “Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis.” JAMA 312.9 (2014): 923-933.
2) Naude, Celeste E., et al. “Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis.” PloS one 9.7 (2014): e100652.
3) Gardner, Christopher D., et al. “Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial.”Jama 297.9 (2007): 969-977.
4) Hu, Tian, et al. “Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors: a meta-analysis of randomized controlled clinical trials.”American journal of epidemiology 176.suppl 7 (2012): S44-S54.