By now, most of us realize that sugar is not a health food and is meant to be consumed in moderation.

Comment: Even better -- don't consume it at all.

It's been linked with poor dental health, obesity, insulin resistance, metabolic syndrome, type II diabetes, cell aging, heart disease, and cancer.

What is less commonly publicized is the link between sugar consumption and liver health.

For years, fat was the subject of a dietary witch-hunt. It was implicated in obesity, type II diabetes, and a myriad of other health problems. The 2004 documentary Super Size Me chronicled the 30-day McDonald's-only diet of filmmaker Morgan Spurlock. During that month, Spurlock consumed 90 meals from the fast-food chain. He gained 24 pounds, his cholesterol level shot up to 230, and fat accumulated in his liver. Those results led many to believe that dietary fat was the culprit, despite the fact that Spurlock consumed over 30 pounds of sugar in that month.

In 2009, filmmaker Tom Naughton released a documentary titled Fat Head, in which he chronicled his own 30-day McDonald's-based diet. Naughton restricted his calories to 2,000 per day and limited his carbohydrate consumption to around 100 grams per day. He didn't limit his fat intake, though - he consumed around 100 grams per day, with about 50 coming from saturated fat. Naughton lost 12 pounds and saw improvements in other health markers during his experiment.

The low-fat craze was based on flawed studies, political bias, and clever marketing by the food industry. It led to the mass availability and widespread promotion of low-fat "foods" like cookies, crackers, cheese, candy, and ice cream. You name it, and Big Food found a way to make it low-fat.

Not only did the low-fat craze fail to improve the health of those who fell for it, it also led to a dangerous increase in dietary carbohydrate consumption - mostly in the form of added sugars. That's because when fat is removed from a food, something has to be added to make it more palatable. Usually, that thing is sugar.

A new documentary that is scheduled for release in 2015 focuses on the impact dietary sugar can have on health. The movie, aptly titled That Sugar Film, outlines filmmaker Damon Gameau's 60-day experiment with a high-sugar diet.

Gameau did not binge on candy, sodas, or other sugary treats. He consumed low-fat foods that are commonly believed to be "healthful."

He explained his food choices to Yahoo:
"I had no soft drink, chocolate, ice cream, or confectionery. All the sugars that I was eating were found in perceived healthy foods, so low-fat yogurts, and muesli bars, and cereals, and fruit juices, sports drinks ... these kind of things that often parents would give their kids thinking they're doing the right thing."
Gameau increased his intake of sugar to 40 teaspoons per day, just slightly more than the average daily consumption of a typical teenager. According to the American Heart Association (AHA), the average American consumes 20 teaspoons of sugar daily. The AHA's daily recommendations for sugar consumption are 6 teaspoons for women and 9 teaspoons for men.

Within three weeks, the previously healthy Gameau noticed his mental and physical health declining:
During the filming, Gameau found the sugary diet affected his physical and mental health, and doctors called his mental functioning "unstable." He also added nearly four inches of visceral fat around his waist, even though he said the diet left him feeling hungry, no matter how much he ate.
He also received a troubling diagnosis: his doctor told him he was beginning to develop fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the accumulation of abnormal amounts of fat within the liver. It is closely linked to the obesity crisis, is a strong risk factor for heart disease and Type 2 diabetes, and in severe cases it can lead to liver failure.

Fatty liver disease rarely causes symptoms until the liver disease is far advanced. At most, there is enlargement of the liver which may cause mild discomfort in the right upper abdomen.

Other possible symptoms include fatigue, weakness, weight loss, loss of appetite, nausea, abdominal pain, spider-like blood vessels, yellowing of the skin and eyes (jaundice), itching, fluid build up and swelling of the legs (edema) and abdomen (ascites), and mental confusion.

The possible complications are serious and include liver failure, gastrointestinal bleeding, and liver cancer.

Unfortunately, NAFLD is becoming more common. It is estimated that 25% of people in the US have it. Adults aren't the only ones who can develop the disease: children can be victims too. There aren't many studies available, but the estimated prevalence among children 2-19 years of age is approximately 10%, the prevalence increases with the degree of obesity, and there is progression to cirrhosis, according to MedicineNet.

In the last twenty years, the prevalence of the disease has more than doubled in teenagers and adolescents.

There are no medications approved to treat the disease, and it is quickly becoming a leading cause of liver transplants.

Sugar is believed to be the main culprit in the development of NAFLD because it is metabolized in the liver and it is known to increase blood levels of triglycerides, a type of fat.

From Well:
Studies suggest that sugar consumption contributes to liver fat accumulation. And there is some data indicating that people who carry genetic variants associated with fatty liver are particularly sensitive to increased fat accumulation in response to sugar and refined carbohydrates.

One of the first pieces of dietary advice that clinicians who treat fatty liver give to their patients is to eliminate sugary drinks from their diets. But doctors say that patients with the disease are typically consuming too many calories of all kinds, not just sugar.
Studies have shown that people with fatty liver disease respond well to the Mediterranean diet, which includes plenty of fresh produce, nuts, olive oil, poultry and fish:
One small clinical trial published in The Journal of Hepatology last year found that a Mediterranean diet had a more favorable impact on liver fat and insulin resistance than a low fat, high carbohydrate diet. And another study in the journal Clinical Nutrition, which involved 90 overweight patients with fatty liver, found similar success with a Mediterranean approach. (source)
Treatment for nonalcoholic fatty liver disease include lifestyle changes (exercise, weight loss, diet), medications, supplements (antioxidants)

In his article titled "Do You Have a Fatty Liver? 90 Million Americans Do!", Dr. Mark Hyman offers some guidelines to help us avoid - or heal - fatty liver disease:
Cut out all high fructose corn syrup from your diet. If you see it on any label for any product - whether it's a salad dressing or ketchup or tomato sauce - don't eat it.

Reduce or eliminate starch. Get rid of white, processed flour. Even whole grain flours can be a problem. It's common to find too much of these starchy foods in the classic American diet, or what we call the SAD (Standard American Diet). All of those things will promote a fatty liver. You may be surprised to learn that it's actually not fat that causes a fatty liver. It's sugar. (To learn more about why this is true, check out Dr. Hyman's book, The Blood Sugar Solution.)

Add some good things to your diet to help heal your fatty liver. Add plenty of fruit, vegetables, nuts, and seeds. Add lean animal protein like chicken and fish. Add good oils like olive oil, macadamia nut oil, avocados, coconut butter, and fish oil. Good fats like these are anti-inflammatory, and they help repair your liver.

Improve your metabolism through exercise. This is a fabulous way to improve insulin resistance and reduce fatty liver.

Eat detoxifying liver-repairing super foods. Focus on the broccoli family. I love this family of foods, and I try to have at least a cup or two every day. Kale, collards, cabbage, Brussels sprouts, broccoli, arugula, daikon radish - all wonderful foods that help repair and heal your liver. Garlic and onions, also, are full of sulfur, which is a great detoxifier.
As for Gameau, he isn't advocating for people to completely cut sugar out of their diets. He told that the experiment's findings suggest a need for more awareness about how much sugar has been added to perceptibly healthy food:
"Sugar's now in 80 percent of the processed food we're eating," he said. "If we can remove that, that's the first step towards making a change."
For more about That Sugar Film, visit the documentary's website.

Here's the film's official trailer.

Additional Resources:

Sugar: The Bitter Truth

The Real Truth About Sugar: Dr. Robert Lustig's "Sugar: The Bitter Truth"

Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease

Sugar Has 56 Names: A Shopper's Guide (A Penguin Special from Hudson Street Press)

The Blood Sugar Solution 10-Day Detox Diet: Activate Your Body's Natural Ability to Burn Fat and Lose Weight Fast