Most of my research on the effects of various types of food on premature death matches most common sense. A modest amount of fruits and vegetables is a good thing. Processed meat is quite unhealthy. Eggs and milk are OK in moderation. Some research, though, surprised me and made me rethink my daily food choices. In this blog post, I’ll share the unexpected outcomes from my research on the longevity effects of good. So let’s dive in and uncover the truth about sugar, canned fruit, processed foods, and potatoes!
1. Sugar is not Evil
Sugar has been vilified recently, with many experts blaming it for the rise in obesity, diabetes, and heart disease. However, while excessive sugar consumption can lead to weight gain, it’s essential to recognize that not all sugar is created equal.
I previously included sugary beverages in my list of “Things that Will Kill You.” This time, let’s talk about sugar not in liquid form — desserts and sweet toppings. When excluding sugary beverages, the 2019 Swedish study found adding sugar to the diet from snacks (cake, cookies, candy, chocolate, etc.) or toppings (jam, syrup, honey, etc.) reduced premature death by 20% or 10%, respectively, for about one serving per day. After that serving, there was no further harm or benefit for consuming more.1 I’ll admit it’s unlikely that myself or readers of this blog are getting less than one daily sweetness serving (about 60 g [2 oz.] for desserts or 10-20g [1 oz.] for toppings), but the critical point is that over that amount wasn’t harmful.
Even fructose, the allegedly most evil of sugars featured in high fructose corn syrup (HFCS), does not seem to affect longevity when not in liquid form. A study of reduced-calorie diets featuring moderate fructose vs. low fructose found more weight loss from the moderate fructose diet,2 and a study that added 30-60g of fructose to a daily diet found no change in lipid or glucose biomarkers.3
2. Canned Fruit Is Bad For You
Canned fruit is still fruit, but its health benefits are reversed into harm when the fruit is packaged in a tin or can. Canned fruit might seem like a convenient and healthy option, but it often contains added sugars and preservatives that negate the benefits of consuming fresh fruit. While one 100g (3 oz.) fruit serving will reduce premature death by about 10%, the same sized serving of fruit from a can will increase the chance of early death by 13%.4
If you’re looking for a way to save fruit, frozen is the way to go. Frozen fruit maintains the healthy nutrients of fresh foods without the sugary and chemical effects of canning.5
3. Preserved Meat or Smoked Foods Are Unhealthy, Not “Processed Foods”
The media often focuses on “processed foods” as bad for you. After reviewing the studies, it’s not clear that there is anything about processing that significantly affects health or longevity. Indeed, many processed foods are healthy, such as whole grain breakfast cereals or breads, nut bars, or hummus.
In 2015, the World Health Organisation (WHO) announced that “processed meats” are bad for you, which they defined as “meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.”6 Note this excludes things like hamburger, which I would consider processed since it’s minced meat, but doesn’t seem to have adverse effects over regular beef, but does include things like ham, pastrami, sausage, and salami. Deli meats, like turkey or chicken slices, would fall into this category.
I prefer to call these preserved meats to clarify that minced meats are no worse than the unminced versions. It seems the chemicals added to meats increase their shelf-life (salts, nitrates, etc.), which cause additional health harm over red meat.
The World Health Organisation (WHO) listed these preserved meats as Class 1 carcinogens, along with tobacco or asbestos.7 Processed meats also increase cardiovascular disease and diabetes risk.8
Since smoked meats also appear in the list, I suspect that smoking food has the same adverse effects on non-meat foods as on meats. Smoking something adds carcinogens and probably other inflammatory chemicals.9 Accordingly, it’s probably wise to avoid smoked nuts, fish, or other smoked foods when seeking longevity and health.
4. Potatoes Are The Healthiest Vegetable
For years, potatoes have been demonized as unhealthy due to their high carbohydrate content and association with fried foods like French fries and potato chips. As a result, many health studies exclude them when talking about how much vegetables people consume. However, when consumed in their natural form, potatoes are a nutrient-dense vegetable packed with vitamins, minerals, and fiber. They are an excellent source of potassium, vitamin C, and B vitamins, which support heart health, immunity, and energy production.
However, all-cause mortality studies show white potatoes are healthier than other vegetables. A 2017 meta-analysis of vegetables found that a serving of potatoes reduced the chance of premature death by 22%, compared with 13% for vegetables overall.10
One way that potatoes are exceptional is how filling they are. A 1995 study reviewed 38 foods to see how filling they were compared with white bread, and potatoes landed at the top of the chart–over three times as filling as white bread. That’s almost twice as much satiety as any other carbohydrate-rich food.11 It’s not fully understood why this is, but one suspect is a protein in potatoes (potato protease inhibitor II) that suppresses appetite.12
Unfortunately, that doesn’t hold for french fries or potato chips. The health benefits of potatoes do seem strong enough to make frying them overall neutral for health and longevity; they’re no longer as positive as other vegetables. I guess it’s better than other foods, like chicken, which shift from a neutral food to statistically harmful food when fried.13
As we’ve seen, many commonly-held beliefs about nutrition may not be as clear-cut as they seem. Nevertheless, we can support our health and longevity goals by staying informed and making thoughtful food choices. So, go ahead and enjoy that baked potato, prioritize fresh fruits, avoid preserved foods, and remember that sugar, when consumed as a dessert or topping, isn’t all bad!