Popular Diets – sensible or sensational?

by | Jan 14, 2014

January is diet month and this is National Obesity Awareness Week, so a perfect time for the British Nutrition Foundation’s symposium on popular diets. I like to make sure I am convinced by the science before I recommend any weight management system, so I couldn’t wait to hear the latest insights from key researchers on the 5:2 diet, low GI diet, high protein low carb diets, Palaeolithic diets, and more. 

We know that you get significant health benefits from losing just 5% of your body weight, and that miracle diets offering speedy and massive weight loss are doomed to failure. But let’s face it, the mantra of eating a sensible varied diet is dull, and one size doesn’t fit all. So the evidence behind popular diets needs to be considered and each one is part of a toolset that dietitians can use to suit the individual; different people will require different strategies that fit with their culture and lifestyle habits.

My take-outs from the day:

  • Research on intermittent fasting shows that it helps to reduce insulin levels in a matter of days. This can improve your sensitivity to insulin, helping to reduce your risks of diabetes.
  • There are many variations to the fasting method of dieting, such as alternate day fasting, and feast on 5 days fast on 2 days. The books on the 5:2 diets aren’t necessarily a true reflection of the research and you can’t just extrapolate from the research by creating a different intermittent fasting plan and expect the same good results. The published evidence is based on fasting for 2 consecutive days (e.g. milk, fruit and veg, 600kcal) followed by five days on a Mediterranean eating plan. That approach for the 5 days makes good sense to me.


  • Research time and time again substantiates the value of low glycaemic diets and better blood sugar control. Fact.
  • There is some evidence on the effect of low GI foods on appetite, satiety and weight loss. High GI diets have been linked to higher insulin levels and overeating.

low GI blog

  • Palaeolithic diets are based on what we were eating in the Stone Age but adapted to modern day habits. They are rich in plant foods – and a huge variety. These foods tend to be low in energy density (fewer calories per gram).


  • Research on high protein low carb diets suggests that this way of eating slows the rate of passage through the small intestine, which facilitates a feeling of fullness.
  • There’s good evidence on the value of controlled very low calorie diets in reducing symptoms of psoriasis, knee osteo-arthritis and sleep apnoea.


In the end, we need to remember the basic message of energy in energy out – if you eat fewer calories than you burn, you will lose weight. Period. I believe it is possible for you to lose and keep the weight off with the right approach and support.

More info on BNF events.




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