Healthy Food & Healthy Living by Dr. Ayala

Can we really blame diabetes on diet choices?

Many chronic diseases are attributable, at least in part, to diet, among them are type 2 diabetes, heart disease and several forms of cancer. 

Type 2 diabetes is an enormous burden on human health and longevity worldwide, It’s has wide consequences for the people suffering from it, and on healthcare systems, as type 2 diabetes affects most organ systems including the heart, kidney, eye, brain, and liver, it increases the chances of cancers, infections, and dementia. 

Type 2 diabetes may run in families, but its rapid rise makes it clear that there’s much more than genetics at play. In the last 40 years type 2 diabetes incidence has risen 5 fold, 1 in 10 adults live with the disease and this is occurring worldwide. It’s clear that diet plays a big role, whether through weight gain and obesity or directly: by affecting sugar metabolism, inflammation, and changes in the gut. 

To what extent does your diet drive the incidence of diabetes, and which foods are most to blame?

To assess that researchers from Tufts University looked at data from 184 countries from 1990-2018. They looked at diet components, as well as age, sex, education, and where people lived. Their model relies on information from the Global Dietary Database, population demographics, global type 2 diabetes incidence estimations, and published research on how food choices impact type 2 diabetes. The findings appeared recently in Nature Medicine.

And the conclusions: about 70 percent of new cases of type 2 diabetes are attributable to a suboptimal diet and could have been avoided with a better diet. Eating too much of the wrong foods – such as refined rice and wheat, sugary drinks, processed and unprocessed meats – can explain 60 percent of the harm. Not eating enough of the protective foods – such as fruits, vegetables, nuts, seeds and whole grains – explains the 40 percent rest of the risk.

Poor diet drives type 2 diabetes in men more than in women, according to the study, in younger people more than in older ones, and in city dwellers more than in rural ones. And although men and city-dwellers with higher education tended to have a greater burden of type 2 diabetes caused by their diet, the opposite was seen in wealthier countries where living in urban areas and a higher education was predictive of a healthier diet. Interestingly, the link between a country's economic development and its diet-attributable type 2 diabetes burden has become weaker over the years – which suggests that as highly processed foods spread worldwide and expand so does type 2 diabetes.

The assessment that 70 percent of type 2 diabetes is diet related is astounding. It’s higher than previously assessed: Another study estimates 40 percent of cases are due to a suboptimal diet. This study, however, looks at 11 dietary factors instead of just six in other studies. Either way, many people could change the trajectory of their health by making healthier food choices and the biggest culprit is refined/highly processed foods – and especially refined carbs.

The diet to prevent diabetes

To lower your risk of type 2 diabetes it's important to control weight gain, which is a major risk factor for the disease. Other important lifestyle risk factors include inactivity and smoking.

Pay special attention to these diet principles to lower your risk:

Skip the sugary drinks: Excess added sugar is an established risk for diabetes, sugary drinks are the leading source of added sugar in our diet, and many studies show a clear link between soda consumption and the development of type 2 diabetes. These include randomized controlled studies that showed that sugary drinks aren’t just associated with diabetes – they cause obesity, insulin resistance and chronic inflammation, which are the harbingers of type 2 diabetes. 

Choose whole, unprocessed foods: Select whole grain over refined grains, eat nuts, beans, legumes, make sure you eat plenty of fruits and veggies (non-starchy vegetables, a potato isn’t in this category).Limit meat, especially processed meat.

Dr. Ayala

The rise and rise of tempting flavor and calorie bombs

Obesity rates have doubled in the US over the past three decades, and are now at about 42 percent. This rise follows a dramatic change in our food environment and our eating habits. Over the last few decades food technologists and food manufacturers have increased and popularized food products that are abundant, relatively inexpensive, calorically dense, and are what’s called “highly palatable”.

What’s highly palatable? A winning formula is one that combines sugars, fat and salt in a way that pleases our reward systems, giving us pleasure. The food industry has been busy making highly processed products from low-cost raw ingredients, and formulating them into super pleasing things to eat. They’re so pleasing that it’s hard to stop eating them – and we’re encouraged to never forget an opportunity to snack on them by massive and ever present marketing efforts.

A new study in the journal Public Health Nutrition examines just how much reformulation occurred in the past decades. While other studies focused on the rise in sugar in the American diet, the authors say theirs is the first longitudinal study of the spread of hyper palatable foods.

The researchers looked at the prevalence of hyperpalatable foods in a statistically representative US food system between 1988 and 2018 using three USDA and CDC food databases. Hyperpalatable foods were identified by criteria that look at the content and proportion of sugars, fat and salt in processed foods.

And the results: Hyperpalatable foods rose by 20 percent in three decades. Hyperpalatable foods now make up 70 percent of available foods in the US! The same grain food items were 50 times more likely to be hyperpalatable in 2018 compared to 1988. Foods in categories such as dairy and meats also went through reformulation, making them more exciting to the palate.

The authors suggest that this reformulation may be one key factor contributing to the rise in obesity: “Our findings indicate that the practices introduced to the food companies in the 1980s focused on product reformulation and enhancement may have had ongoing deleterious effects on our food system, contributing to the current obesogenic food environment in the US.”

An interesting finding is that the biggest rise in hyperpalatable foods was in ones with extra fat and salt – these are meal items and savory foods, rather than desserts and sweets. This may represent the expansion in frozen and ready to heat meals.

Resisting temptation

The authors call for public health policies limiting the addition of fat, sugar and salt to processed foods to below the threshold of hyper-palatability. 

Since that’s unlikely to happen anytime soon, the personal health solution is to minimize highly processed foods and prepared meals as much as possible. There’s a reason it’s so hard to stop eating highly processed foods – they’re designed to entice and to leave you wanting more, while at the same time giving you little nourishment. 

In this food environment it’s no wonder vegetables and fruit find it so hard to compete for attention.

Dr. Ayala

This is how weight is gained

Although people blame vacations, holiday meals and older age, weight is actually gained slowly and steadily over a lifetime. Much like you don‘t notice the slow bodily transformation from teenager to young adult to middle aged, as there’s no clear demarcation, weight stealthily adds up unnoticed – until it is.

More than 40 percent of the adult US population is obese, and since obesity is a risk factor for a multitude of chronic diseases – including stroke, heart disease, diabetes and several cancers – understanding how weight is gained can help mitigate this raging epidemic.

A new study in the Journal of Obesity looks at weight gain over a decade of almost 14,000 statistically representative Americans. The results are concerning.

Over 10 years more than half of the people followed in the study gained 5 percent or more body weight, more than a third gained 10 percent body weight or more, and a fifth added 20 percent.

Weight gain over the decades

The study shows an inverse relationship between age and weight gain. The greatest weight is gained by young people – between 20s and 30s – in which an average of almost 18 pounds of weight is added on.

Between 30s and 40s weight gain averages about 14 pounds. It slows further down to about 10 pounds for the 5th decade of life, and to 5 pounds for the sixth.

This pattern adds up to 47 pounds over four decades.

People usually think that older age and slower metabolism leads to the accurate observational finding that the older the population the greater the obesity incidence. This is not the case according to these findings. 

In fact, people gain the most weight when they’re young, but despite gaining 18 pounds by the mid 30s many young people are not obese – it takes further weight gain to push you into the obese category.

Obesity rises with age because the older you are the more years you have to steadily gain weight, a process that actually starts early on.

Why would weight gain slow down with age? One reason is that the bigger the body, the more energy it needs, so if you gain significant weight in your 20s and 30s, if you continue eating the same amounts you’ll gain less weight in subsequent years. 

Habits over time

We’ll all age with time – it’s inevitable. But we don’t have to get fatter over the decades – that’s avoidable with better eating and exercise habits.

It's mostly eating habits – lifelong habits – that determine weight gain trajectory.

Studies in overfeeding, in which people were fed 1000 excess calories daily for three weeks led to more than 4.5 pounds gained. But the excess weight was lost within 6 weeks after the overfeeding experiment ended. Extend that to 100 days – which is what was done in another study – and weight gain was on average 18 pounds, and although much of the weight was lost when the experiment ended, 3 extra pounds lingered, and the participants continued to gain weight over the years. 

It's what you do day in and day out that matters the most.

It’s wise to take inventory of your eating habits early on (and it's never too late), add highly nutritious healthy foods such as fruits, vegetables and whole grains, and cut out unhealthy, seductive calorie bombs, such as highly processed foods, foods with lots of added sugar, and sugary drinks.

Dr. Ayala

How much junk food is too much?

There’s a place for everything that’s tasty and enjoyable to eat in a healthy diet, that’s what I believe. I can also support this declaration with plenty of scientific literature showing that long lived communities as well as large cohorts in studies maintained health and avoided excessive weight gain without abstaining from dessert – traditional diets don’t declare abstinence from sweet or fried foods.

It’s the proportions that matter. If 90 percent of what you eat is nutritious you can play with the rest. If 80 percent of your days are reasonably active, hibernating couch-potato style on a lazy day will do no harm.

But here’s the problem: Our proportions have turned upside down, completely. 

Junk all around

A new study in the Journal of Nutrition assesses the amounts of junk food in the American diet using two nationally representative data sources, including more than 10,000 people.

What is junk food? The academic literature struggles with this question. Salty snacks, candy and soda are the hallmark representatives, but there are many other products – such as bakery products, sweet breakfast cereals, fast-food and processed meats – that should be in the eat-less/junk category.

This study uses the 2016 Chilean law for food labeling and advertising definitions of junk food. This law identifies foods with high caloric density, high added saturated fat, sugar and salt, and imposes marketing and advertising regulations upon them, including warnings on the front label and a ban from sales in schools.

And the results: Between 2015-2018 almost half of daily calories US adults consumed were derived from junk food. Sugary drinks composed almost half of the sugar from these junk food.

This study paints a picture concordant with another study in kids, that finds that 56 percent of the calories US kids consume come from junk food.

This current study also found that there are disparities in junk food intake among ethnic groups, with non-Hispanic black adults consuming more junk food, and with the highest income group consuming the lowest amount of sugary drinks.

You are what you eat 

Obesity, type 2 diabetes, hypertension and many other chronic conditions are nutrition associated diseases – they could be avoided or ameliorated by a healthy diet and lifestyle.

We know that the more junk food in a society’s diet the greater the obesity rates. A recent large prospective study found that a 10 percent increase in ultra-processed food is associated with a 10 percent increased risk in overall cancer and breast cancer rates. A study following 12,000 Americans with no underlying illnesses for more than two decades found a 30 percent higher risk of dying in the group consuming more junk food.

If people just replaced junk foods they’d likely gain less weight and perhaps shed some.

A study in the BMJ simulated what would happen if kids reduced their junk food intake, and estimated that childhood obesity rates would drop from 20 to 11 percent, and there’s be 16 percent fewer overweight kids. This simulation extrapolates from a randomized controlled trial in which people alternated between highly processed and less processed diets which were matched for total calories, energy density, carbs, protein and fat, fiber, sugars and salt and instructed to eat as much as they wanted. People on a junk food diet consumed on average an additional 500 calories daily than they did on an unprocessed diet.

You know it when you see it

As to the definition of junk food, no system of categorizing food will be perfect, and we can debate whether warnings on the front of the package are the best way to reduce the intake of what’s inside.

Although academics may struggle with the definition of junk food, for the most part, we know junk food when we see it. The problem is that we see so much junk that it's normalized. Mainstream supermarket’s shelves sell more highly processed and junk food than wholesome ones, pharmacy and convenience store shelves stock almost nothing but junk, and advertising efforts focus almost only on these products. 

It’s really no surprise that half of what Americans eat is junk when so much of what’s offered to them in reality and digitally is these highly processed sugary drinks, candy, fast food, mass produced chips, highly sweetened cereals and cured meats.

Dr. Ayala

No, it doesn't just go through

A new study finds that a common food additive, ubiquitous in processed foods, changes the microbiome and the gut of healthy people

The introduction of highly processed food upon a society reliably predicts a decline in people’s health.

Highly processed food is linked to rising obesity rates and high blood pressure. A large study found a 10 percent increase in ultra-processed food was associated with a 10 percent higher risk of overall cancer and breast cancer. A study in Public Health Nutrition following 12,000 Americans with no underlying illness for more than 20 years, found that a highly processed diet is linked to a 30 percent higher chance of dying early.

Why is processed food harmful?

The convenient, flavorful, ready to eat array of processed foods are low in important nutrients: micronutrients, fiber, and the whole array of what’s in whole foods.

On the other hand they contain much of the things we try to eat less of: sugar, fat and salt.

And then, on top of that, they contain ingredients that the human intestine had never ingested until the advent of these technological innovations: Hydrogenated oils, food coloring, chemical preservatives and emulsifiers are just some of them. The nutrition label lists many ingredients foreign to human food, which up until recently came solely from nature. 

A new study in the journal Gastroenterology looks at emulsifiers – these are a hallmark of highly processed foods, added to improve texture and increase shelf life. Besides natural emulsifiers, such as lecithin, which was originally derived from egg yolk and can also be extracted from plants, there are synthetic emulsifiers such as carboxymethylcellulose (CMC) which are commonly used in industrialized foods. CMC was approved for use in the 1960s, despite no extensive testing, and was presumed to be safe because it’s poorly absorbed and is eliminated in our stool.

In the 60 years since the introduction of this emulsifier we’ve learned that even when something passes through our gut without entering our blood stream it still leaves its mark. Our gut bacteria encounter this substance and it may change the composition of the microbiome; the lining of the gut, the mucosa, which comes in contact with whatever’s just passing through, might also be susceptible.

And indeed, CMC has been shown to promote inflammation, metabolic syndrome and obesity in mice, to induce colitis – bowel inflammation – in predisposed mice, and also to change the mice’s microbiome. But that’s mice. Researchers set out to check CMC’s effect in humans.

The randomized controlled feeding study was conducted at the University of Pennsylvania, and included 16 healthy volunteers. After an 80 hour emulsifier-free diet at home, the participants were randomly assigned to an emulsifier free or one with 15 grams per day of CMC, in a residential setting in order to assure all elements of diet and exercise. 

And the results: CMC clearly changed the composition of gut bacteria, reducing select species and overall diversity, and there was a significant depletion of some of the beneficial bacterial metabolites that are known to help maintain a healthy gut.

Besides looking at fecal composition and metabolites, the researchers also performed sigmoidoscopies before and after the trial, and took biopsies of the distal colon in order to study the gut lining microscopically. In two volunteers on the CMC-containing diet, they found that bacteria were encroaching into the lining – a finding reminiscent of what you can see in people with inflammatory bowel syndrome and metabolic syndrome. This may suggest that when the health of the microbiome is compromised, or due to the CMC exposure, the altered gut bacteria start invading the lining – which when healthy is normally close to sterile.

Emulsifiers ubiquitous in processed foods

This is a small study, and just one chemical component is examined here. In real life people consume many food additives and their precise quantities are unknown. But even in this very short study there were stark changes in gut bacteria, reduction in beneficial fecal metabolites and in a few of the participants, even changes in the lining of the gut.

The authors conclude: “our observations argue that a particular food additive might perturb the host-microbiota relationship to promote disease in a subpopulation of individuals.”

So while individual susceptibility to processed foods’ ingredients may play a part, the highly processed diet is not good for anyone, for the other reasons listed above, and it’s probably one of the worst diets one can eat.

Because besides the low nutritional value, and the unnatural non-food stuff in it, it’s also built for overeating, crafted to please us and to manipulate our reward system. Food chemists design these products with a perfect sugar-fat-salt and flavor combinations, great mouthfeel, chuggability and crunch, making them so pleasing and easy to eat that they’re hard to resist or to moderate.

If there’s one small dietary commitment you want to sign on to for the coming year I suggest it’s to look more carefully at over-processed foods, and replace at least some of them with wholesome ones. A recent study in JAMA shows that two thirds of calories American kids eat now come from highly-processed foods, so we really do have our work cut out for us. 

Dr. Ayala