Dec. 21, 2020

The Harvard Sugar Study & The Fat-Free Food Boom

Sarah starts the episode off with the history and origins of refined sugar, including our innate preference for sweet foods and a quick lesson in carbohydrates. 

Becca then discusses the infamous Harvard sugar study of the 1960s and the decades of repercussions on the food industry, research, and consumer buying habits. She then breaks down some of the scandalous marketing strategies created by the sugar industry and how they reinforced the “fat-free” food boom. Becca & Sarah then consider the implications of industry-funded research, including the impact on dental research, weight-loss recommendations, and the anti-inflammatory effect of avocados.

For a full list of references, visit our website.

Note: Sarah misspoke and said breastmilk contains mostly maltose, but the main sugar in breastmilk is actually lactose.

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Ahmed, S. H., Guillem, K., & Vandaele, Y. (2013). Sugar addiction: Pushing the drug-sugar analogy to the limit. Current Opinion in Clinical Nutrition and Metabolic Care, 16(4), 434-439. doi:10.1097/MCO.0b013e328361c8b8

American Public Media. (n.d.). A duty to starve. Retrieved from 

The Associated Press. (2016 Sep 13). CBC. Sugar industry paid scientists for favourable research, documents reveal. Retrieved from

Aubrey, S. (2020). Beware the 'bliss point' in food. The Press (Christchurch, N.Z.)

Bee Culture (2016). The Chemistry of Honey. Retrieved from: 

Canadian Sugar Institute (2019) Canadian Sugar Institute – Highlights of Statistics Canada Sugars Consumption Report. Retrieved from: 

Centers for Disease Control and Prevention (2020). Know Your Limit for Added Sugars. Retrieved from:,called%20by%20many%20different%20names. 

Diabetes Canada (2020). Sugar and Diabetes. Retrieved from:,on%20a%202000%2Dcalorie%20diet&text=Limit%20intake%20of%20sugar%20sweetened,drink%20water%20in%20their%20place 

Diabetes Co UK (2020). Simple vs Complex Carbohydrates. Retrieved from: 

Falbe, J., Thompson, H. R., Patel, A., & Madsen, K. A. (2019). Potentially addictive properties of sugar-sweetened beverages among adolescents. Appetite, 133, 130-137. doi:10.1016/j.appet.2018.10.032

Government of Canada (2018). Sugars. Retrieved from: 

Hamamichi, R., Asano-Miyoshi, M., & Emori, Y. (2006). Taste bud contains both short-lived and long-lived cell populations. Neuroscience, 141(4), 2129-2138. doi:10.1016/j.neuroscience.2006.05.061

Kearns CE, Schmidt LA, Glantz SA. Sugar Industry and Coronary Heart Disease Research: A Historical Analysis of Internal Industry Documents. JAMA Intern Med. 2016;176(11):1680–1685. doi:10.1001/jamainternmed.2016.5394 

Lovelace, B. (2019 May 7). Cambridge University report says Coca-Cola’s academic research funding comes with a hitch. It can kill studies it doesn’t like. CNBC. Retrieved from 

Meach R. From John Yudkin to Jamie Oliver: A Short but Sweet History on the War against Sugar. In: Gentilcore D, Smith M, editors. Proteins, Pathologies and Politics: Dietary Innovation and Disease from the Nineteenth Century. London (UK); New York (NY): Bloomsbury Academic; 2018. Chapter 7. Available from:

Meule, A., & Gearhardt, A. (2014). Food addiction in the light of DSM-5. Nutrients, 6(9), 3653-3671. doi:10.3390/nu6093653

Nakrani MN, Wineland RH, Anjum F. Physiology, Glucose Metabolism. [Updated 2020 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan. Available from: 

Sifferlin, M. (2015 Mar 10). The Sugar Industry Shaped Government Advice On Cavities, Report Finds. TIME. Retrieved from

Skerrett, P. J. (2011 Apr 26). Is fructose bad for you? Harvard Health Publishing. Retrieved from 

Smith, A. F. (2015). Sugar: A global history. London: Reaktion Books.

Union of Concerned Scientists. (2017 Oct 11). How Coca-Cola Disguised Its Influence on Science about Sugar and Health. Retreived from 

World Health Organization (2015). Guideline: Sugars intake for adults and children. Retrieved from:


B: Today we are going to cover the history of sugar, then do a deep dive into the1960’s Harvard study that changed the portrayal of sugar and fat for the food industry and in the minds of consumers everywhere. Then I will briefly go into a few other sneaky things I found out throughout my research. This episode is a little bit more about scandal in the food industry, as the instances I will tell you about weren’t technically criminal. But I must say, they are equally as interesting and cringeworthy.

S: Today I am going to tell you all about a wonderfully divisive product that everyone loves to hate - SUGAR! 

It’s been called addictive (which isn’t exactly true, but it does activate a reward circuit in our brain by triggering dopamine - a neurotransmitter that makes us feel good) and sugar has also been blamed for everything from poor obesity and non-communicable disease to hyperactive children and poor dental health. 

So, a bit of a bad rep, but humans love sugar or at least the taste of it! We have over 10000 taste buds and each one of them has receptors for sweetness. Most scientists think we evolved to prefer and seek out sweet foods because from a survival standpoint, it helped us identify safe and energy-dense foods in nature, plus human breast milk is sweet - about 40% of the calories in breast milk come from a form of sugar called lactose, which is a molecules of glucose bound to a molecule of galactose. 

Now speaking of glucose - a quick carbohydrate lesson. Today we are going to be talking about classic table sugar - the white crystallized powder that we put in everything from baked goods to processed foods, so we’re going to be mostly talking about the added sugar. And this is the form of sugar that has been linked to all sorts of health concerns and can raise blood sugar very quickly after consumption. 

But there are a wide variety of different types of sugar that occur naturally in foods called the simple carbohydrates, and these are the shorter chains of sugar molecules, things like mono- and di-saccharides. Some common ones are glucose, fructose, maltose, galactose, lactose, and sucrose, and they occur in fruits, vegetables, grains, and dairy products and they are a source of energy and nutrition. Simple carbohydrates are our bodies most efficient source of energy because they are digested into the ultimate simple carbohydrate - glucose, meaning that when we consume polysaccharides and disaccharides in our food, they are broken down into glucose through digestion and then shuttled through a process called glycolysis, which breaks down glucose and gives us ATP that our body uses for energy! 

Becca, I thought it would be fun if you could tell us about the citric acid cycle. 

Simple carbohydrates aka. sugars from things like bread, fruit, vegetables, dairy products, etc. are great for giving the body the energy it needs to survive and maintain bodily functions. When we consume these whole food sources of simple carbohydrates aka sugars, we are also typically consuming fibre and vitamins and minerals. However, when we talk about added sugars like granulated table sugar is typically pure isolated and refined sucrose, which means that it only provides energy or kilocalories. This is why you might have heard people referring to added sugar as “empty calories” because you’re not getting any useful macro or micronutrients, it’s just pure sucrose, which is quickly broken down to glucose in the body. 

As the food system has become increasingly industrialized over the past couple centuries, sugar has played a very important role as a preservative, texture modifier, fermentation substrate, flavouring and colouring agent, bulking agent - and of course, as a sweetener! Sugar is often added to help food manufacturer’s achieve “bliss point” - the perfect balance of salt, sugar, and fat where the flavours combine to make food taste amazing. 

So classic white refined sugar, or table sugar, which I’ll just call sugar from here on out - comes from sugar canes or sugar beets, both crops give us the exact same end product (100%) sucrose. The crops are harvested, chopped up, boiled to extract all the sucrose, and then you’re left with a super sweet syrupy liquid that gets purified, crystallized, dried, and packaged. Something interesting I learned while researching is that during the purification process, which takes the sugar from a brown colour to a white colour, animal bone char (which is animal bones that have been charred to ash so it’s basically just dust) can sometimes be used for sugar made from sugarcane but not sugar made from sugar beets. Something to watch for if you’re vegan! 

The earliest records of sugar cultivation occur nearly 10000 years ago by indigenous peoples in New Guinea, primarily for animal feed but people would also chew on sugar cane to enjoy the sweet flavour. The earliest records of sugar manufacturing, so actually crystallizing sugar and making it into a form similar to what we know today, originated in India about 2000 years ago and then spread to the Middle East, the Mediterranean, and Egypt. For centuries, sugar was a very expensive luxury and a status symbol. At wealthy parties, feasts would include elaborate sugar sculptures and wealthy guests would be given sugar as gifts. It was also used to sweeten bitter medicines, but it was not widely consumed by the public. 

The reason why sugar was so expensive is because, at this time, harvesting and processing sugar was incredibly labour intensive and there was a shortage of manpower. So, how did sugar transition from being a luxury item to a household commodity? Well, in three words: Europe, colonization, and slavery. It began when the Portuguese and Spanish colonized and set up sugar plantations in Madeira, Porto Santa, and the Canary islands - these are all islands off the North West coast of Africa, near Morocco. These islands had the ideal climate for growing sugarcane, and they were inhabited by indigenous peoples that could be enslaved. 

Christopher Columbus made a voyage to the Caribbean in 1493 and he made a pit stop in the Canary Islands to grab a seed cane (a stalk of sugar cane that can be replanted) and he introduced sugarcane to Hispaniola (which is Haiti and the DR today), and by the early 16th century, he established plantations in Puerto Rico, Jamaica, Cuba, and eventually Brazil. However, with the constant wars and introduction of communicable disease, an estimated 80-90% of indigenous populations died off during the first century of colonization and this resulted in a shortage of manpower. 

So again a shortage of manpower. The solution? Exporting African slaves to Brazil. And this is the model that America eventually adopted as well. Sugar was called “white gold” as it fueled the growing wealth of European nations. Sugar production became huge in the United States, by the mid-1800s, Louisiana alone was producing 25% of the world’s sugarcane using the enslaved population. This is probably not surprising, but the labour required to work on the plantations or in the sugar mills was absolutely brutal - around-the-clock work, undernourishment, and very low life expectancies were common among slaves. & I think we’ll have to revisit the injustices of sugar agriculture in another episode because the human cost of sugar harvesting is still extremely high. In Nicaragua, there are some areas where sugar plantation workers have a life expectancy of 46 years, and they fall ill and die quite rapidly of chronic kidney disease and researchers’ leading theory is that it’s due to the heat stress and chronic dehydration experienced while harvesting sugarcane. I watched a Nat Geo documentary called “Under Cane” and the farmers expressed that they don’t get mandatory breaks, don’t have access to shade, and are often sub-contracted to avoid liability. So sugar has a very dark history and the industry is clearly still not perfect. 

Now, let’s talk sugar in Canada - the climate in Canada is not suitable for growing sugarcane, but we do produce sugar beets in Alberta. Apparently, per capita sugar consumption in Canada has not increased since the 1940s, but that doesn’t mean we’re not consuming quite a bit. The Canadian Community Health Survey from 2015 indicates that Canadians are getting nearly 20% of their daily energy from total sugars, with nearly 9% of that coming from added sugar, which is actually a fairly reasonable amount. This is probably because the amount of added sugar in the marketplace and in processed foods has actually declined over the past 20 years, and on average, is ⅓ less than food products in the US.  

The World Health Organization recommends limiting free sugar intake (so, remember, those are the sugars added during processing) to less than 10% of total energy consumption. So in a 2000 calorie diet, 200 calories would come from sugar, which works out to about 50g/day, or about 12 teaspoons - which, when you think about it, seems like quite a bit! And there is a lot of sneaky sugars in food products like bread, spaghetti sauce, yogurts, granola bars, so it’s actually not too hard for that sugar intake to add up. 

Now, if you are looking to decrease your sugar intake, you can check the food labels for sugar, but it’s likely that it will be disguised as another name! Some names to watch out for are: anything ending in -ose (galactose, maltose, sucrose, fructose, glucose), molasses, honey, maple syrup, brown rice syrup, corn syrup, fruit juices, fruit juice concentrate, etc. 

& that is your brief intro to sugar!!! 

B: Sarah - what are your initial thoughts about the Harvard sugar study? How much do you know?

If you haven’t heard about this scandal, you have likely been living under a rock, or you were born in the last 5 years. Because this was HUGE. 

Growing up in the 90’s I remember “low fat” food products being all the rage. Low fat dressings, crackers, everything! But with less fat, more sugar is often added to makeup for flavour and texture. It wasn’t until recently, like within the last decade, that we started digging into some past research on the topic. And it was found that some of the foundational research done on sugar and fat was influenced by the sugar industry themselves

The key resources I used in my research include an article by the Associated Press called “Sugar industry paid scientists for favourable research, documents reveal”, research by Kearns, Schmidt and Glantz called “Sugar Industry and Coronary Heart Disease Research: A Historical Analysis of Internal Industry Documents.”, some others including an article from TIME magazine, all of which you can find in our show notes.

So, let’s start at the beginning. It’s 1964. After WWII some research came out linking sugar to heart disease and the sugar industry is taking a bit of a hit. They are looking to do some damage control, so the Sugar Research Foundation, which is now called the Sugar Association launched a campaign to address the claims and the negative impact that they were having on sugar sales (The Associated Press, 2016). 

I am going to quickly read you the copy from one sugar advertisement that I found from TIME magazine in 1964. It has a happy-looking child on it with pigtails who is rollerskating. Here is what it says:

Technically that last line is true; however, this ad is promoting the consumption of sugar to boost the energy levels of children. And knowing what we know about sugar now, this is extremely problematic.

In 1965, while marketing campaigns like this took place, the Sugar Association (which is what I will call them moving forward as that is their current name) also approved something that they called “Project 226”. And it was in this project that involved paying the equivalent of about $50,000 USD to Harvard researchers to review the current literature on sugar and fat and to produce some new and improved research (The Associated Press, 2016). The Sugar Association set the objective of the research - to look at the role that fat and carbohydrates play in heart disease - they provided some articles to include in the research and received drafts of the findings throughout the research process (Kearns, Schmidt & Glantz, 2016).

In 1967 the Harvard article was published by the New England Journal of Medicine. The three authors were made up of MD’s and PhD’s; so very credible players in terms of science. The research indicated that in order to prevent heart disease, ONLY two dietary interventions were necessary: reducing cholesterol and saturated fats (The Associated Press, 2016).

There are a few issues here: 

Number 1. The sugar industry’s role and associated funding were not published with the research. BUT it wasn’t until 1984 that the Journal requested disclosures regarding funding. So technically, at the time, by keeping this information concealed, they weren’t doing anything wrong. Now this would not fly.

Number 2. To this day there is still “no appreciable relationship” (appreciable = large enough to be noticed) between dietary cholesterol and heart disease. However, it is recommended to limit the amount of saturated fat in the diet - so they got that part right (The Associated Press, 2016).

  • I do feel like the cholesterol and heart disease combo is one that has been argued for decades, so I want to quickly break this down so that it makes sense.
  • Cholesterol is a waxy substance that is actually a steroid. And for all you science brains out there, you likely know that steroids are actually a part of the lipid family tree - so they are a type of fat. This means that they are insoluble in water; so they don’t dissolve in water. This is why having a high blood cholesterol can be dangerous - as it floats around in your arteries, potentially leading to plaque buildup. This might eventually limit the amount of blood going to the rest of your body, presenting some problems.
  • HOWEVER, cholesterol is also 100% necessary for us to stay alive as it creates the structural membranes around every single cell in our body. Because it is so essential to our being, our bodies actually create it. This is why it is also found in animal products - their bodies create it to survive too. So by eating animal products, you are eating their cholesterol.
  • I know that it would make sense if eating cholesterol raised your blood cholesterol, but this really isn’t how it works. You body highly regulates the amount of cholesterol it has in it; so if you eat more cholesterol, your body will produce less. If you eat less cholesterol; your body will produce more.
  • I know that this may sound frustrating to someone who has high blood cholesterol, but the way to lower it has not been proven through a decrease in dietary cholesterol. Lifestyle changes like exercise and even consuming cholesterol-lowering foods have way more evidence to back them up. (legumes, nuts, avocados)...
  • Anyways, that’s your crash course in can see that research like this definitely confused A LOT of people. Scientists and dietitians included. It changed recommendations and consumer buying habits for years. 

I guess I was numbering off issues with this research before I went on that tangent. So the third issue here is that while the association is not fully understood, there is a link between sugar and an increased risk of heart disease. So by blaming fat for heart health issues, the Sugar Association was throwing the food industry and consumers off their scent (The Associated Press, 2016).

Beyond this study, the sugar industry played into this sugar vs fat debate with their marketing campaigns, and you can tell that they used evidence similar to the results found in this study to make their claims. Since there really is no association advocating for dietary fat (since it is found all over the place) there was really no notable rebuttal. It was essentially scientists vs the industry and media - and in many cases scientists trusted these published results. 

I have some more examples of sugar advertisements from the 1960’s and 70’s. And they are shocking. This one has an image of a woman smiling with a cup of pop/soda. And it says:


  • Using diet culture to sell sugar claiming that it can curb your appetite. 

This next one is SO much worse. It just has a picture of what looks like a glass of Coke on it:

  • Promoting sucrose like it is a health product or essential nutrient
  • But I do agree that sugar can be part of a balanced diet...

We do need carbohydrates, so this is true. Almost all of our cells use glucose as their main form of energy. It is either used right away, or stored for later. And when sugar or sucrose is digested it breaks down into both fructose AND glucose. So yes, it also gives us that quick source of energy. But whereas glucose can be used as energy by all the body’s cells; fructose is almost entirely metabolized in the liver. One of the end products of this metabolic process are triglycerides, which are a type of FAT. If these triglycerides build up in the liver it can lead to what’s called nonalcoholic fatty liver disease; and if these triglycerides are released into the bloodstream, they may contribute to more plaque in the arteries. High blood sugar overall may also contribute to insulin resistance, which is a precursor to type II diabetes (Skerrett, 2011).

The thing to remember here isn’t that fructose is bad. It is that a buildup of excess sugars in the body may lead to health issues. As always, moderation is key.

But back to this story - While the rest of the world didn’t really question this research until 2016, so about four years ago, there was one scientist who was trying to warn the general public about sugar from the getgo. And that’s John Yudkin. He was a physiologist and nutritionist who from the 1940’s - 1980’s wrote several books on sugar’s link to obesity and heart disease. Yet no one really listened to him, which is unfortunate, because he passed away in the 1990’s and didn’t get to see the world’s dietary patterns change based on some of his initial claims (Meach, 2018).

  • The other school of thought was Ancel Keys, who wasnt the most ethical scientist. 
  • Unethical treatment of 36 otherwise healthy individuals. He conducted the starvation studies during WWII; to study those who had been deprived of food and their reaction to refeeding.
  • The birth of refeeding syndrome.
  • Lead to depression, hysteria, hypochondriasis, edma, self-mutilation; one man even cut off 3 of his fingers with an axe, but was so out of it they didn’t know whether they had some it as an accident or intentionally (American Public Media, n.d.)
  • Ancel Keys was one of the key players in discrediting Yudkin’s work 

Let’s now fast forward to 2016 when some researchers, including Cristin Kearns, a former dentist, released a paper for JAMA Internal Medicine. It contained 31 pages of correspondence between one of the Harvard researchers and the Sugar Association. These communications did reveal that there was a bit of a cover-up occurring; and that the sugar industry also tried to counter other research that indicated links to other health issues such as diabetes (Kearns, Schmidt & Glantz, 2016).

Following this 2016 paper being published, the Sugar Association did make a statement that they "should have exercised greater transparency in all of [their] research activities," but that disclosures weren’t commonplace then. They also stated that the JAMA authors were attempting to “reframe historical occurrences" (The Associated Press, 2016). So still not really owning up to anything.

However, this paper was pivotal in the food industry and in reframing what constitutes a “healthy” diet. As we know, research plays a fundamental role in literally everything that we know about nutrition and science. It impacts what is reported in the news, it guides future research and it also sets the stage for new trends and marketing strategies.

Harvard University was a reputable source then, and is a reputable source now, so for years healthcare professionals used this initial research in practice - reducing cholesterol and saturated fat to prevent heart disease. And they left sugar out of the equation. While they were right about saturated fat, it skewed our perceptions of both cholesterol and sugar in a way that some people still argue about their points to this day. But I do think that most consumers are finally starting to make peace with the fact that we were lied to for quite some time and take into consideration the benefits of dietary fats, specifically those of unsaturated fats.

But it would be silly of us to think that this was the only instance of deception on the part of the sugar industry. In the 1960’s and 1970’s the sugar industry also had influence over the US National Institutes of Dental Research and shifted the focus from sugar intake as the culprit of cavities. Even though the scientific director of this Institute stated that:

“on logical grounds and good evidence,...if we could eliminate the consumption of sucrose, we could eliminate the problem…We are realists, however, and we recognize the value of sucrose to nutrition.”

So there was a little corruption all over the place. The Sugar Association did comment on the recent publication of these findings in TIME magazine in 2015. They said:

“It is challenging for the current Sugar Association staff to comment directly on documents and events that allegedly occurred before and during Richard Nixon’s presidency, given the staff has changed entirely since the 1970s. However, we are confused as to the relevance of attempts to dredge up history when decades of modern science has provided answers regarding the role of diet in the pathogenesis of dental caries… A combined approach of reducing the amount of time sugars and starches are in the mouth, drinking fluoridated water, and brushing and flossing teeth, is the most effective way to reduce dental caries.” (Sifferlin, 2015).

I find it funny that they phrased it as the “amount of time sugars” are in the mouth.

Anyways, I think people keep dredging this up because they want to make sure that the food industry is being honest and transparent now. And by discussing these events publicly, we raise consumer awareness. I think the sugar industry knows this, but just wishes the history would just go away

To this day research is still frequently funded by large food industry leaders. Coca-Cola has funded research out of the University of Colorado to focus on exercise rather than caloric intake for optimal weight loss (Union of Concerned Scientists, 2017). It was even found in some of their contracts with researchers from 2015 - 2016 that they could “quash studies” or “pressure researchers using the threat of termination” (Lovelace, 2019).

If you watched the documentary Game Changers, you might remember the shocking claim that they shared about avocados. And this was that avocados can “modulate the inflammatory response caused by one hamburger meal”. What wasn’t disclosed was that this study was conducted on only 11 people and was funded by the Hass Avocado Board.

So this really does happen ALL THE TIME. And a lot of research wouldn’t be possible without industry funding. But there is a debate as to whether or not taking this type of funding is ethical to the research process since it might lead to biased or falsified results. Some say that it can be used as marketing for the industry, and that this research may actually affect the legitimacy and trust of other research without industry funding.

And while some nutrition professionals are very much against it, others seem to be okay with it as long as disclosures are made. As sometimes this research can lead to real discovery and other research. And I should note that funding disclosures are now integrated in peer-reviewed or credible research, however, the funders role in the research is not always specified. SO industry-funded research should be valued below other public health or nutritional sciences research.

Right now, these disclosures aren't always made in news coverage of these topics either which can lead to consumer confusion.

Moral of the story here is to question the things you hear. Check sources and where funding is coming from, especially when claims seem to go against common knowledge or when they are being used to promote a product.