The French Paradox is a term used by food scientists/ dieticians to describe how highly pleasurable foods in small doses may in fact enhance satiety and food satisfaction, and thus contribute to maintaining a lean body frame (like we see with French women!).
The French Paradox may be under attack, by Dr. Pierre Dukan, the latest guru to compile a high protein diet that would put Dr. Atkins to shame. The biggest draw of the plan being that one can eat as much as desired just as long as there is not a single gram of carbohydrate – and very little fat – for the next few weeks. Unlimited arugala and egg whites – oh the joys.
The idea of ‘unlimited’ is just… so totally Anglo Saxon, which is to say nothing of the idea of a restrictive diet. The presence of this plan suggests to me that obesity may no longer be just a North American and British problem: even the French are starting to get fat! Today I am going to attempt to explain why high protein diets can work for the short term. I have taken great pains to avoid clichés revolving around water retention, or clumsy jabs at describing craving reduction.
If anything underscores the We Mean Business Message, its a French doctor who forgoes the pleasure – and health benefits! – of Olive Oil. So, with an equally serious tone, here is why High Protein Diets work (for the short term).
WHY THEY WORK TEMPORARILY
You may surprised to learn that High Protein diets actually have a fair amount of psychological science in their favour. Many find it significantly easier to eat fewer calories on these plans due to the boring nature of eating lean meat. In other words, if you had previously consumed a high carbohydrate diet, and replace it with a high protein, lo carb diet, you will very likely lose weight. But this theme is a little deeper than an impossible feat of binge eating egg whites (do I need to find empirical sources here?).
I did get in touch with my good friend and fellow Sensory Scientist, Emma Bertenshaw. Her work has shown that pleasantness ratings of drinks – in High Protein versus High Carbohydrate varieties – go down significantly for the Protein type drinks (Same flavour, same taste profile, etc. Thus, protein, for some reason, leads to a psychological difference in the way that pleasure is perceived).
We have three important factors that contribute to an overall limitation of caloric intake when following a lo carb diet:
a. Less access to food
b. Higher thermogenesis
c. Reduction in a pleasure during the eating episode (thanks Emma!)
d. maintenance or accretion of fat-free massin some individuals, a moderately higher protein diet may provide a stimulatory effect on muscle protein anabolism, favoring the retention of lean muscle mass while improving metabolic profile.
Problematically, however, high Protein diets have yet to be accepted by journals with an impact factor greater than 3. Take, for example an article written in the Lancet where (Astrup, 2004), authors wrote:
Fat has a low thermogenic effect, and although a high-protein diet might increase 24-h energy expenditure by 23 % such an effect cannot account for more than a small fraction of the observed weight loss.
However, when I consulted a second review (in journal with less impact), written also in 2004, I found that within a comparison of 14 other empirical studies, the thermogenesis achieved with High Protein versus High Carbohydrate or Low Protein diets actually ranged between 4-14.6%. The greater the protein ration, the greater the thermogenic effects.
It is in fact true that the typical thermic effect of protein ranges between 20-35%, whereas that for carbohydrates and fat ranges between 5-15%. Thus, an important question is to determine whether this increased thermogenic aspect of protein ingestion can be translated into an overall reduction of consumed calories.
SENSORY SPECIFIC SATIETY, AND TASTELESS FOOD
The part I find most interesting is the possibility that high protein diets enhance Sensory Specific Satiety faster than carbohydrates. SSS relates to our ability to continue sampling foods even after we have been satiated. During times of famine, this was a beneficial trait: those organisms that can consume food beyond their caloric needs have a greater probability of surviving a famine. A great way to increase caloric intake is by eating a variety of foods.
I looked on google and found an oldish paper, Higher-protein foods produce greater sensory-specific satiety, and authors looked at high protein versus high carbohydrate sandwiches and yogurt. It turns out that the high protein versions of both foods led to a decrease in hunger and a more rapid decrease in pleasantness. Which just confirms Emma’s point, that high protein diets may simultaneously taste worse and be more satiating.
I guess that’s one strategy. Dieting behaviour is based on such intimate individual differences that this kind of approach may not be feasible for you. But I guess if I can save you a trip to the book store, the post was worth it.
Halton, Hu (2004). Journal of the American College of Nutrition, Vol. 23, No. 5, 373385 The Effects of High Protein Diets on Thermogenesis,
Satiety and Weight Loss: A Critical Review
Lancet Report: http://www.skepticreport.com/sr/?p=680
Astrup A, Meinert Larsen T, Harper A. (2004) Atkins and other low-carbohydrate diets: hoax or an effective tool for weight loss? Lancet. 2004 Sep 4-10;364(9437):897-9. Review.
Vandewater K, Vickers Z. (1996). Higher-protein foods produce greater sensory-specific satiety. Physiology & Behaviour. 59(3):579-83.