Why We Crave Sugar, but not Lettuce or Broccoli


Sugar cravings have kept countless numbers of people from staying on a diet, and is one of the leading causes of the growing diabetes and obesity epidemics.

As you may know from personal experience, many people will continue to eat snacks and treats containing high amounts of refined sugar (and white flour, which the body treats in almost exactly the same way) no matter how much they want to give up these harmful foods.

In fact, people have been known to continue eating their favorite sweet foods even when their doctor says it’s killing them.

Everyone knows it isn’t easy to stop eating sugar, but most people don’t really understand why. Why is chocolate cake and a big plate of spaghetti on many people’s list of “comfort foods,” while a big plate of steamed broccoli is not? Why do we continue to fill up on ice cream and candy, even when we really aren’t hungry? Why do cravings for a sweet snack seem almost impossible to ignore?

The easy way to explain it is to say “sugar is addictive.” It’s true, but it doesn’t really explain the root of the problem. We still need to explain why it’s addictive, when other foods are not.

The answer lies in evolutionary biology. (Those who don’t believe in evolution can substitute the term of their choice.) What it all boils down to is simple survival – not our own survival, but the survival of our ancestors – the ones who lived long before a few bright engineers built the first machines to refine pure sugar and pure starch from common edible plants.

Daniel C. Dennett, author of Darwin’s Dangerous Idea, states the issue quite plainly in his latest book, Breaking the Spell:

People generally say that we like some things because they are sweet, but this really puts it backward: it is more accurate to say that some things are sweet (to us) because we like them! (And we like them because our ancestors who were wired up to like them had more energy for reproduction than their less fortunately wired-up peers.) There is nothing “intrinsically sweet” (whatever that would mean) about sugar molecules, but they are intrinsically valuable to energy-needing organisms, so evolution has arranged for organisms to have a built-in and powerful preference for anything that tickles their special-purpose high-energy detectors. That is why we are born with an instinctual liking for sweets – and, in general, the sweeter the better. [emphasis added]

To put it plainly, our brains have special ways of rewarding us for going to all the trouble of finding sweet, nutritious fruit. A very similar set of rewards is given to anyone who goes to the trouble of catching a nice fat antelope.

Sugar and fat both give the body needed energy, but they give us far more than that.

The fruits our ancestors ate because they were sweet contained micro nutrients that keep people healthy (no vitamin pills back then…). Some of these vitamins and minerals keep our immune system functioning properly, and may even give some protection against cancer.

And the fat in that antelope allowed some of those vitamins (the oil-soluble ones) to be absorbed into the body. Sweet things and fat things, in small quantities, are necessary for our health.

We are rewarded for eating sweet foods by a burst of pleasure that comes when we bite into something sweet and juicy (some people find this more pleasing than others do, which explains why some people have a sweet tooth, and others don’t).

The reward continues when we experience a feeling of well-being that comes when a little shot of serotonin is released into our brain. This chemical is a neurotransmitter that affects our sense of well being, and helps to moderate our moods, our sleep cycles, and our appetite. Our serotonin goes up (temporarily) when we eat something sweet.

There is no surprise that obesity and depression are so closely linked, since low levels of serotonin can lead to depression, and this can cause many depressed people to crave sugar to get that little burst of mood-elevating chemical. However, the more sugar you consume, the less effective it is in improving your moods – so people compensate by eating more sugar in an unending cycle.

Even when depression is not a problem, most people who consume sugar daily will suffer from physical withdrawal symptoms when they cut back or remove all sugar from their diet.

Like we read at the beginning of the article, sugar is addictive.

Removing refined sugar and white flour from your diet completely is hard to do, but it is definitely good for your health. But removing all sweet things from your diet is not good for you, and will simply cause such intense cravings that you’ll go off your new diet completely.

Although we desire sugar because it’s the sweetest thing we can eat, our bodies are really craving the vitamins, micro nutrients, and energy that come from eating fruit. To stop eating sugar without replacing it with fruit will set your diet up for failure before you ever begin.

So, why isn’t broccoli addictive? Simply because roots, leaves and other edible wild plants were usually quite easy to find, and simple hunger would drive most people to eat them. This also explains why we search out sweet food even after we’re completely full from eating a healthy, delicious meal – we don’t seek out sugar because we’re hungry. We do it because eating sugar feels good – as nature intended.

What nature didn’t intend was the sugar refining machinery and candy industry and the distribution system that has been created in the last 200 years, allowing us all to eat pure, refined sugar without eating the fruit it originally came packaged in. That’s why sugar addiction is a new phenomenon, one that creates an epidemic of obesity and diabetes in every country where refined sugar and flour are easily available and affordable. We’re fighting an industry that has turned a natural product into it’s pure, chemical form, and we are not well equipped to handle the fight alone.

Many scientists are looking for a pill or potion that can “fix” our cravings for sugar. In a way, this is a way of saying that there is something wrong with us because we continue to crave the tastes that our bodies were originally designed to love. The craving for sweet food kept our ancestors alive for millions of years before the sugar industry was created. Since the desire for sweet foods is part of our natural survival system, it seems unlikely that a drug will ever be found to solve this problem.

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3 thoughts on “Why We Crave Sugar, but not Lettuce or Broccoli

  1. I have to disagree with you simply because I am actually addicted to broccoli. I’ve eaten a broccoli based diet for over 3 months now. I just can’t stop eating it. I am eating a large plate of steamed broccoli with baby bellas snow peas and carrots right now. Am I just more evolved that those who still seek to satisfy the cravings of their ancestors? I still like sweets a few times a week. Most of the time my sweets are an organic dark chocolate bar. Anyway, I’m interested in hearing your response to this.

    • I am not the writer of this article but I do agree with you, however. Either you’re more highly evolved than most, or your late ancestors or more recent ancestors did not receive much broccoli in their diet, causing you to have a stronger addiction to the vegetable. I do believe that the article is still justifiable, though.

  2. Deborah, this article does not include brain working. Human brains change and adapt constantly so over time, the wiring of your brain can change to associate happy memories n positive things with brocolli. various factors influence things in life. however not everyone is aware of everything. So around the world, take in the good points from this article for example, and if you have questions go and seek answers on google. And the best way for you to live in this world is to understand evolution and cognitive neuroscience. these two things will resolve all issues in life u ever had. cheers.

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