A lot changed in the food system after the 1970s — not just what people ate, but how food was grown, processed, marketed, and consumed. In the 1970s, Americans were not fat. Well, only 14-15% were classified as obese. Childhood obesity was approximately 5%. The obesity rates remained fairly constant throughout the 1950s and 1960s.
Unfortunately, obesity rates began a sharp climb in the late 1970s and then accelerated through the 1980s to present.
According to the CDC (Centers for Disease Control and Prevention) data from the National Health and Nutrition Examination Survey (2021-2023), 40.3% of U.S. adults were obese. Of the 40.3%, 9.7% were classified as severely obese and 31.7% were classified as overweight. The survey also found that children, between the ages 2-19 years old were 21.1% obese. Of these 21.1%, 7% of children and adolescents were classified as severely obese and 15.1% were classified as overweight.
These numbers are record-high obesity rates for children and adolescents. I noticed that the study claimed that the adult obesity rate has dropped slightly from 42.8% in 2017-2018 to 40.3% in 2026. I can only reasonably assume that one of the major contributing factors to this slight decline is the flood of weight loss drugs since 2016.
Let’s go back in time to the 1970s and the 1980s, which happens to be the time that I grew up. So, I am very familiar with the time period. In America, the majority of people just weren’t fat. This was not because they had the willpower to refrain from eating so much. The food and lifestyles were very different back then. What happened next only guaranteed the inevitability of weight gain for most people. This overall weight gain of Americans didn’t occur over several generations but within a single lifetime.
The food environment wasn’t just about people making bad choices in their food selections, the food choices changed. The portions of food became larger. The ingredients in food production changed. The food availability increased with the number and size of the supermarkets. Even the lifestyles changed.
By the 1970s, 95% – 96% of the American households had one television. Only a few had two or more. Throughout the 1970s, households were limited only to only a few channels. I remember this well. In Los Angeles, these channels were 2, 4, 5, 7, 9, 11, 13 and possibly channel 52, depending upon how good our rooftop antenna was. It was in the 1970s and 1980s that cable saw it’s golden age. Several networks were launched: HBO (1972), WTBS (1976), ESPN (1979), CNN (1980), MTV (1981).
It might sound strange writing about obesity and adding a section about the televisions, but it really impacted the lifestyles of most children. If you also couple this with the release of the gaming consoles, like the Atari 2600 in 1977 and the Nintendo Entertainment System (NES) in 1983 then the Sony PlayStation in 1994. These gaming consoles have become a major part in the daily routines of not only children but of young adults and some older adults now too. This has led to lower energy expenditure, reduced cardiovascular fitness, porr posture from prolonged sitting, eye strain and fatigue from extended screen time. All leading to the increased risk of obesity.
Growing up, I don’t remember our family having a gaming console and if we did, we may have only two games which got old quick. This was a time before Blockbuster and game rentals in 1985. I didn’t get much of an allowance and had a paper route for a while before starting my first job at, you guessed it, McDonald’s. My older sister had the car which unfortunately she drove it with the oil light on and burnt out the engine. I had to either ride my bicycle or walk to go anywhere. I remember doing a lot of walking as a child, whether to the park, to my friend’s house and even to work.
These changes weren’t the only contributing factors to our lifestyles. Some changes had improved convenience and food safety.
Here are the biggest shifts:
In the 1970s, many families still cooked most meals at home using basic ingredients. Today, a large percentage of calories come from industrially processed foods.
These foods often contain refined flour, also known as white flour, all-purpose flour, or maida, is produced by removing the outer bran and the nutrient-rich germ from the wheat grains, retaining only the soft, starchy endosperm. This process gives the flour a white color, finer texture and a longer shelf life compared to the whole wheat flour. It also may undergo bleaching and conditioning to enhance its appearance and baking qualities. Unfortunately, the process significantly reduces the fiber, vitamins, mineral and antioxidants. This also results in a higher glycemic index (sugar level).
Another contributing factor started back in the 1950s with a physiologist, Ancel Keys, who was famous for researching diet and heart disease after World War II. He believed that saturated fat raises cholesterol and high cholesterol contributes to heart disease. Keys is associated with the “Seven Countries Study” where he examined the diet from the populations in Italy, Greece, Japan, Finland, Netherlands, Yugoslavia and the United States. The study found correlations between higher saturated fat intake, higher cholesterol, and higher heart disease rates.
The results of the observational study showed associations, but not direct proof that saturated fat alone caused heart disease. Even though the other factors vary between countries, they were smoking, activity levels, sugar intake, processed food consumption, stress, body weight and overall diet quality.
This caused a hysteria in the nutrition community where the U.S. government adopted dietary recommendations encouraging Americans to reduce saturated fats, reduce cholesterol and eat more carbohydrates.
This was the tip of the iceberg because the fallout from this study also affected the food companies. When fat is removed from foods, the flavor suffers, texture suffers and the overall satiety declines. So, the food manufacturers needed to replace the fat with something else. This ended up being added sugars in most everything, refined starches, corn syrups and additives. This led to products such as low-fat cookies, fat-free yogurt which were loaded with added sugars, and marketed sugary breakfast cereals as healthy and the best way to start your day.
Since added sugars dramatically increased. By the 1980s and 1990s, In order to keep the cost down, the food manufacturers started using high-fructose corn syrup. High-fructose corn syrup became widespread because it was cheap and heavily subsidized through corn production policies. High-fructose corn syrup does not trigger our body’s ability to feel full and the lack of any nutritional value, just makes us want to consume more. Sugary soda consumption surged and processed snack foods exploded (With ads like the Lay’s potato chips, “You can’t eat just one.) Processed food and even food made at restaurants were produced not with beef tallow or butter but with industrial seed oils, artificial flavors, emulsifiers and preservatives.
Documents revealed that the sugar industry funded researchers in the 1960s, who seriously downplayed the role of sugar in heart disease while emphasizing the saturated fats instead.
Americans began consuming more liquid calories, refined and processed carbohydrates and hidden sugars.
One criticism of the Ancel Keys study was that he “cherry-picked” countries that supported his hypothesis and excluded the countries that did not. Researchers increasingly connect ultra-processed diets with obesity and chronic disease.
One of the largest changes was the explosion of ultra-processed foods — packaged products engineered for long shelf life, convenience, and hyper-palatability.
Anyone who goes to the supermarket will see the whole rows of sugary cereals. Also foods like frozen dinners, chips and snack foods, fast food, protein bars, sweetened yogurt, soda and sports drinks.
Sugar consumption changed and not for the better. Sugar intake increased sharply beginning in the late 1970s and 1980s, especially from sweetened beverages.
Portion sizes got larger all on the notion that big was more value for your money. Larger soda sizes. A typical fast-food soda in the 1970s was often 7–12 ounces. Today, they are 32–64 ounce drinks. Restaurant portions are dramatically larger. Snack foods are sold in oversized bags. “Value meals” encouraged overeating.
This shift changed people’s perception of normal serving sizes.
Traditional fats like butter, lard and tallow were increasingly replaced with industrial vegetable oils like soybean oil, corn oil, canola oil and cottonseed oil
Soybean oil consumption especially exploded after the 1970s.
These oils are inexpensive and stable for processed foods and restaurant fryers, but critics argue the dramatic rise in omega-6 fatty acid intake may contribute to inflammation when combined with modern diets.
In the 1970s, home cooking was more common. Family dinners were more regular. Now, on the basis of convenience and maybe a little bit of laziness, Americans consume more fast food, use delivery apps, eat out at restaurant and consume more convenience foods. Of course, these foods make up a much larger share of calorie intake, sodium, sugar and seed oils.
Even our farming has become more industrialized. Agriculture shifted toward monoculture crops, heavy pesticide use, large-scale feedlots, faster-growing livestock, synthetic fertilizers. Foods became cheaper and more abundant, but critics argue nutritional quality and soil health declined.
Our meat and dairy production changed. Livestock meant for food were increasingly, grain-fed instead of pasture-raised, raised in confined feeding operations, and given antibiotics more routinely.
This changes the fat composition, omega-3 levels and farming practices
Our food became available 24 hours a day, seven days a week. In earlier decades, fewer late-night options existed, snacking was limited based on availability. And now we have multiple convenience stores, delivery services, drive-thru, and vending machines. All resulting in near-constant eating opportunities.
Food marketing became much more aggressive. Food companies became extremely sophisticated in flavor engineering, advertising psychology, targeting children and creating cravings. Bright packaging, mascots, and addictive flavor combinations became major business strategies.
With the increase in artificial ingredients such as artificial sweeteners, food dyes, emulsifiers, stabilizers, and flavor enhancers. Some scientists are studying whether certain additives may affect our gut microbiome, appetite regulation and inflammation though evidence varies by ingredient.
Many researchers think it’s the combination of these lifestyle and food-system changes — not one single ingredient — that explains much of the rise in obesity and chronic disease since the 1970s.
