Dr Susan Swithers hails from Purdue University in West LaFayette where she is a Developmental Psychobiologist. Phew, that is some title Susan. The Green Man has hankered after a swish sounding title like that for some time now, something along the lines of Aboreal Antiquarian perhaps. Anyway, enough frivolousness. In spite of the fact that The Green Man thinks that Susan has got a bit carried away when thinking up a title she is doing some interesting work in the area of obesity.

It seems that diet soft drinks have a role to play. There is one simple reason why most people are fat and that is that they consume more calories per day than they burn. This raises the question of how you know, in normal circumstances, how much to eat. The answer, according to Susan, is that we learn, at a subconscious level, how many calories are in food based on its characteristics.

There are a number of characteristics that we use, sweetness is one and consistency is another. Both of these we can fool and this leads to a reduction in our ability to monitor and regulate our consumption of calories to match our requirements. Looking at each of these in turn. The increasing consumption of sweet low calorie food means that the relationship between sweetness and calories breaks down in our subconscious and our natural tendancy to feel sated after a small amount of these foods is removed.

Similarily the body does not treat thick liquids as as satisfying as solids even though they may contain an equal number of calories. Yes folks, the "thick shake" is one of the principal enemy combatants in the obesity war.

If the break down of our ability to regulate our intake of calories is a real phenonemon and it is linked to the consumption of diet drinks then another statistic suddenly becomes very interesting. Between 1987 and 2000 the number of Americans consuming diet drinks rose from 70 million to 160 million. During the same period consumption of non-diet soft drinks rose by 15 gallons (57 litres) per person per year. Yes you read that correctly 15 gallons per person increase.

Taking a holistic view of the problem we see that this is a symptom of our general loss of connectedness with our bodies. We are vesting the responsibility of maintenance of our bodies in others and we are doing this because it is easy and self-indulgent. Water will quench your thirst, there is no need to sweeten it even with calorie free sweeteners. Your hunger will be sated by grains and pulses just as well as with hamburgers. If they take more effort to prepare then you have burnt calories preparing them. In food, faster is not better. Try visiting SlowFoodUSA and learn about the "slow food" alternative to the fast food culture that pervades the west.

Read more of Susan Swithers' research here.