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US diets have improved – but Americans still eat too much sugar and fat, study finds

Americans’ diets have improved substantially – but they’re still mostly made up of empty or low quality calories, a new study finds. 

People in the US were eating fewer empty carbs – which mostly come in the form of added sugars and more whole grains, plant protein and fatty acids in 2016 than in 1999, Harvard University researchers report. 

Encouraging though those improvements are, they are made over a low baseline. 

Most calories should from complex sources – like whole fruits, vegetables, nuts and legumes – but currently more than half of Americans’ consumption is low-quality food, rich in simple carbs and saturated fats prevalent in frozen and fast food. 

And fat intake has actually increased over the past 18 years – a trend in the wrong direction for better health.  

People in the US are eating complex carbs and protein (light blue) from whole foods than they were in 1999, but fat consumption is up (yellow) and saturated fat intake remains high 

Poor nutrition is a risk factor that drives some of the top killers of Americans: heart disease, type 2 diabetes and several cancers, including the increasingly common ones of the colon and rectum. 

In fact, obesity is now considered the third-leading cause of both death and years of healthy life lost to disability.  

Yet over 60 percent of women and nearly two-thirds of men in the US are either obese or overweight. 

Scientists have learned so much about the importance of good nutrition to overall health that doctors even prescribe diet adjustments, and public health professionals are pushing for the practice to become both more widespread and individualized. 

Slowly but surely, their attempts have been paying off. 

Information about what makes a good diet is slowly trickling out to the general public. 

To assess these slow shifts, Harvard University researchers analyzed data on nearly 44,000 US adults and their eating habits between 1999 and 2016. 

Over the course of that time, the proportion of Americans’ diets made up carbohydrates fell from 52 percent to 50 percent.  

Carbohydrates are supposed to make up between 44 and 65 percent of your diet, according to the most recent Dietary Guidelines for Americans. 


The Western diet is loosely defined as one full of fatty and sugary foods, such as burgers, fries and soda.  

People often eat foods that are high in

  • Saturated fats
  • Red meats
  • ‘Empty’ carbohydrates
  • Junk Food

And low in

  • Fresh fruits and vegetables
  • Whole Grains
  • Seafood 
  • Poultry 

Health effects have been linked to things such as hypertension, heart disease, diabetes, obesity, colorectal cancer and dementia. 

But there’s caveat: low quality carbs found in sugar do not get processed the same way and are not as nutritionally valuable. 

These still comprise about 42 percent of the average American’s diet. 

And over 20 percent of that came from refined grains, fruit juice and potatoes. 

Much of the 42 percent was also made up added sugars to fruits and beverages.  

Worse yet, after fat consumption fell from 1971 to 2000 in the US, between 1999 and 2016, it crept up from comprising 32 percent to 33 percent of the average American’s diet. 

Americans aren’t eating more of the good fats – such those found in eggs, avocados and oily fish like salmon – either. 

Saturated fats found in fried and processed foods still make up more than 10 percent of our diets.  

Despite growing evidence that plants not only provide sufficient, but healthier protein, most of what Americans eat comes from red meat, either unprocessed or processed. 

Meanwhile, people in the US still get precious little protein from seafood, nuts, proteins and legumes. 

What gains have been made in Americans’ diets on the whole are almost washed out when you look only at the nutrition of poorer or less educated groups. 

‘We know that intake of high-quality carbohydrates is very low but it’s very encouraging to see this trend toward improvement,’ says study co-author and nutrition researcher Shilpa Bhupathiraju. 

‘For as long as we can remember fat was replaced by refined carbs, removing bran and fiber,’ she adds. 

But now, to reduce the burden of obesity in the US, Americans need to focus on eating whole fruits, vegetables, grains and legumes and to limit frozen and fast foods,’ she says.