Study shows a ‘primal’ diet can bring rapid weight loss and health benefits

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On Monday I started a blog about the artificial sweetener aspartame with a reference to my preference for a diet rich in natural, unprocessed foods. Such a diet might be described in various ways including a ‘hunter-gatherer’, ‘caveman’ or ‘paleolithic’ diet. However such a diet is described, the aim is the same: to feed the body with foods that have been long-time elements of the human diet. This way, in theory at least, we’ll be giving the body the foods it has evolved to eat, and are therefore the best for it.

My belief is that there’s an abundance of evidence that going back to basics with our diet is the way forward for individuals wishing to optimise their health. And a recently-published study seems to have added to this body of evidence.

The study in question tested the impact of a ‘paleolithic’ diet in 20 men and women aged 20-40 [1]. The dietary instruction given to participants of this study were as follows:

Foods permitted in unlimited quantities:
All fresh or frozen fruits, berries and vegetables except legumes, canned tomatoes without additives except for citric acid, fresh or frozen unsalted fish and seafood, fresh or frozen unsalted lean meats and minced meat, unsalted nuts (except peanuts), fresh squeezed lemon or lime juice (as dressing), flaxseed or rapeseed oil (as dressing), coffee and tea (without sugar, honey, milk or cream), all salt-free spices.

Food permitted in limited quantity:
Dried fruit (2 days/week), salted seafood (one meal/week), fat meat (one meal/week), potatoes (two medium sized/day), honey (used in marinade once/week), cured meats (as entrée once/week), mineral water (only when drinkable tap water was not available).

Prohibited food:
All milk and dairy products, all grain products (including maize and rice), all legumes (beans, lentils, peanuts), processed meats (e.g. sausages, pâtés), canned food (except tomatoes, see above) and all forms of confectionery, ice cream, sorbet, soft drinks, juices, syrups, liquor, sugar and salt.

Individuals were instructed to eat this diet for 3 weeks. 14 of the 20 individuals who volunteered for the study actually finished it.

Compared to what they had been eating previously, eating the paleolithic diet led to a significant reduction in overall food intake (about 900 calories less per day on average). Fat consumption reduced by about 20 g per day, but more notably, I think, is that carbohydrate consumption fell by 177 g per day on average (it has been previously been noted that primitive diets tends to be lower in carbohydrate than a typical Western diet [2]). The paleolithic diet also was higher in vitamin C and lower in sodium than the baseline diet.

After just 3 weeks, there was significant change in a number of measurements. Most notably, these were:

An average weight reduction of 2.3 kg (about 5 lbs)

An average reduction in waist circumference of 1.5 cm (about ½ inch)

An average reduction in systolic blood pressure (the higher of the two blood pressure readings) of 3 mmHg (mm of mercury)

A 72 per cent reduction in the levels of a substance known as plasminogen activator inhibitor-1 (this would be expected to reduce the clotting tendency of the blood, which might translate into a reduced risk of heart attack and stroke)

This study is somewhat hampered by the absence of a control group (a group eating a diet against which the paleolithic diet could be compared) and its small scale (just 14 people). However, its results mirror very much what I find in practice: when individuals move their diet in a primal direction, they very often end up eating less quite naturally, and also will tend to shed weight with relative ease as a result. Also, the results from such a dietary change, in my experience, can be quick (as this study demonstrates).

Longer-term studies of a paleolithic diet would be nice to have. However, in their absence, all we have to go on is our experience. Here again, mine are generally positive. Because eating this sort of diet usually allows individuals to lose excess weight without hunger, it is something that individuals tend to find sustainable in the long term, which obviously ups the chances of good results in the long term too. Generally speaking, I reckon going back to our nutritional past is the way forward for those seeking to lose weight and optimise their health.


1. �-sterdahl M, et al. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. European Journal of Clinical Nutrition 2008;62:682″685

2. Cordain L, et al. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr. 2000;71(3):682-92

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