16/04/2015 10:33 BST | Updated 15/06/2015 06:59 BST

Sex, Drugs, and Milk Chocolate: Why Fad Diets Fail

'I hate chocolate' said no one, ever.

Sex, drugs, and milk chocolate. Has it really come down to this? Can we place milk chocolate amongst some of the most pleasant (and elicit) substances and activities on the planet?

You'll notice I've emphasized milk chocolate here. In addition to personal preference, my background in Experimental Psychology and Neuroscience factor largely into my bias about global chocolate preferences. Both areas provide a unique platform for understanding human appetite, and in light of the obesity pandemic, it is clear our appetite has gone awry.

Whether we look at the food industry, our genes, or changes in technology that foster sitting- as opposed to moving- it's also clear that we are eating more and moving less. However, the knee jerk reaction to fast, detox, or use a fad diet is never the remedy. Just as we would never impulsively run a marathon, we should never drastically cut calories. However, for some bizarre reason, the latter feels like a rational thing to do. Well obviously. There are scores of books, magazines, and outside influences touting the inflammatory consequences of everything from sugar to fat to wheat. Fat, after all, is a tissue of inflammation.

Looking at the success of fad diet books alone, we might convince ourselves we need to lose weight- and... fast! It's always Fast! Here, I'd like to use some of the findings in cognitive neuroscience and the neurobiology of eating behavior to address, specifically, why fad diets don't work.

The most obvious reason, is that stress and impulsivity often undo the work we've tried to achieve with a diet. If the plan is too restrictive, it may inadvertently encourage binge eating (which, most dieters already know).

Some fascinating parallels between obesity and addiction based research exist, and one is the fact that both food and drugs 'feel' better when we're hungry.

Scientists have known about the latter fact for years. Drugs may have more hedonic and reward impact in states of energy depletion. In terms of food, we experience enormous pleasure if we eat when we're hungry. This is even more true if we're famished and then consume... Milk chocolate. It's the contrast, not necessarily the food, that encourages over consumption. This of course, is one of the central factors in establishing habitual overeating patterns.

Treats will unleash a flood of neurotransmitters like endogenous opiates, dopamine, and kickbacks from the endocannabinoid system. This reaction is particularly strong if we are hungry. Therefore, the more dramatic the food restriction, the stronger the attraction to pleasant food becomes.

Psychologically, we're all prone to wanting things that feel 'naughty', and the physiological aspects of overeating are also important: the restriction will contribute to a greater flood of neurotransmitters in the brain, confusing it into thinking that binge eating is actually a healthy behavior.

Relinquishing to craving may occur due to stress, sheer availability, or even curiosity. Many people simply want to remember what the forbidden milk chocolate tastes like, unwittingly setting themselves up for a binge.

Not eating enough, a hallmark characteristic of any fad diet, is negligent. We trick ourselves into thinking we can quickly lose weight, but the short-lived caloric slash simultaneously increases the value of the foods we need to learn to manage.

Fad diets fail because they encourage drastic caloric reduction, often relying on the elimination of entire classes of macro nutrients. The fad diet pendulum swings between the expulsion of either carbohydrates or fat, which is ultimately a cheat sheet way of cutting calories. The 90's Atkins diet is today's Gluten Free fad. Problematically, this creates space in the market for foods to address everyone's 'intolerance', and we trick ourselves that eating a few Atkins bars is better than succumbing to a few chocolate buttons. This only sets us up to find the chocolate buttons hugely appealing once we 'give in'.

Finally, can I go on record here? I really don't believe 'kale' is an appropriate answer to long term health and weight management. It's a really great cruciferous vegetable: it's not a panacea for weight related issues.

Reminding ourselves that 'food and drugs feel better when hungry', underscores the danger of not eating appropriately. Hunger makes food more pleasurable, not less. Portion control is an essential strategy, and something we all have to learn in order to navigate our current food environment of abundance.

'Don't fool yourself, for you are the easiest person to fool', were wise words spoken by theoretical physicist Richard Feynman. Weight loss is not theoretical physics, but It would appear there's a place for it in dietetic advice: that's one of the best recommendations out there.

In short, eat nice food with caution and moderation, and your brain and body will get to the place they need to be, if they're not already there in the first place.