Paleo, Quit Sugar or 5:2?

In the early 1550s, a Venetian merchant by the name of Luigi Cornaro published a book titled La Vita Sobrab (English: “The Sober Life”), on what he called “the art of living well.” Finding himself near death at the age of 55, Cornaro modified his eating habits on the advice of his doctors and began to adhere to a calorie-restricted diet, limiting himself to only 300 grams of food daily. In his book, he counselled readers on a life of frugal meals, exercise and temperance as ways to live a long and healthy life. While there’s some debate over whether this is the first “diet” ever published, there’s absolutely no debate that we’ve been inundated with almost every diet imaginable in the 450 or so years since Cornaro published his book.

In developed countries, people are getting sicker and sicker, with obesity rates skyrocketing and chronic disease on a steady climb. It’s no wonder that a great deal of time and effort is being put into trying to find the solution for this rising wave of ill health.

But rather than moderation, diets these days seem to focus on a radical change, with many authors purporting to have found the real reason why we’re getting sicker as a society and happily offering the latest list of foods we should be banishing from our cupboards.

Three diets, all with different approaches, have been gaining popularity recently, with promises of health, vitality and a return to “the way we were meant to eat.” As with every way of eating, there are good and not so good points to each one, so what’s the good we can take away from this latest wave of dietary dogmas?

The Paleo diet

The Paleo diet, sometimes referred to as the caveman diet, is based on what’s claimed to be the eating habits of prehistoric humans. Followers of this diet avoid processed foods, grains, dairy and legumes, and eat a diet based on fruits and vegetables, grass-fed meats, fish, nuts and certain starchy vegetables such as sweet potatoes. But experts have questioned the evidence for the rationale behind this diet.

Benefits. Having minimal or no processed foods in the diet can be a great goal. Processed foods packed full of sugar and fat and low in fibre, vitamins and minerals definitely aren’t needed in a healthful diet. The simple aim of trying to eat more foods as close to their natural state as possible is an excellent first step toward healthy eating.

Concerns. However, while minimising processed foods in the diet can do wonders for health, the same can’t be said for avoiding wholegrains and legumes. Research has shown that eating one to two servings of wholegrains every day can lead to a reduction of 20 to 30 per cent in cardiovascular disease, diabetes, stroke and some cancers.

Similarly, legumes have been shown to be a good way to extend one’s life, with a 7 to 8 per cent reduction in the risk of death seen for every 20-gram increase in the daily consumption of legumes. A diet completely avoiding these two foods isn’t just restrictive; it’s potentially completely missing out on the health benefits these nutritional powerhouses can provide. The Paleo diet also has the potential to be very high in meat and animal products, which is a serious concern, given the large body of evidence linking high red meat intake to a greater risk of several chronic diseases.

The "I quit sugar" diet

Sucrose, the table sugar you buy at the store, is made up of two other sugars—fructose and glucose. The “I Quit Sugar” eating plan, unlike what its name suggests, is not about cutting all sugar out of the diet. It actually focuses only on avoiding fructose. Fructose is found in slightly higher amounts in common sweeteners such as high-fructose corn syrup, which is used heavily in sweetened processed foods in North America. 

The other half of sucrose—glucose—is allowed, as are more complex carbohydrate sweeteners.

Benefits. By reducing the consumption of fructose, the plan eliminates a large range of processed foods from the diet, which can lead to better whole-food choices.

Concerns. The name of the diet isn’t entirely accurate, because it focuses on giving up only oneparticular kind of sugar—fructose. Many of the recipes adhering to this diet include ingredients like rice malt syrup, which, while not high in fructose, is still a sweetener and it’s high in other forms of sugar. The insistence on avoiding fructose in all forms can also lead to the complete elimination of otherwise healthful foods that naturally contain fructose, such as whole fruits. Also, while reducing sugar in the diet is certainly not a bad thing, such a strong focus on only one component of the diet can lead to an overconsumption of other foods such as red meat, high amounts of which have been linked to increased rates of colorectal cancer.

The 5:2 diet

The 5:2 diet asks participants to eat freely five days of the week, with the other two days being “fast days,” in which women eat only 2000 kilojoules and men eat only 2500 kilojoules (the recommended daily kilojoule intake is 8700). The diet is said to mimic the feast or famine situations humans often found themselves in during past centuries. Without this steady stream of food, weight loss is said to come from an overall restricted kilojoule intake for the week.

Benefits. Intermittent fasting and moderate kilojoule restriction have been practised by a wide range of societies over the years for religious, cultural or simply practical reasons, and a body of evidence suggests that such practices can play a role in increased longevity. An example of this is the traditional Okinawan diet, which incorporates the principle of eating until you are 80 per cent full. Such a restriction can also lead to a person becoming more aware and appreciative of the food they are choosing to eat—connections that can be easily lost in a world of eating in front of the TV and consuming large amounts of convenient and fast foods.

Concerns. The kilojoule content of foods isn’t the determining factor in whether foods are healthful. By focusing on kilojoule content, followers restrict their energy intake on fast days, but don’t necessarily fill their meals with vital nutrients. Also, while being aware of the food choices we make each day is a great thing, 2500 kilojoules is not a lot of food, making it hard to stick to this diet. An example of a 2500-kilojoule day could be a boiled egg with a small piece of toast for breakfast and an evening meal of about 100 grams of chickpeas tossed through salad greens with a small cup of milky herbal tea. Such a tight restriction might lead someone to fixate too much on quantity rather than quality.

On the other hand, nonfast days have no restrictions, meaning that for five days a week, those who practise the 5:2 lifestyle could be eating a typically poor, high-kilojoule modern diet and a kilojoule-restricted version of this same poor diet for the remaining two days.

Summing up

Ironically, when you combine what each of these diets does well, you’ll find a pretty similar message to what Signor Cornaro recommended centuries ago, which in turn has a lot in common with the teachings of many other traditional cultures. A modern diet that’s packed with plant foods that are as close to their natural state as possible is a robust foundation for building a healthy diet that’s stood the test of time. It has served people well in the past and it can serve us well in the present, helping to ensure that we have a long and healthy future. 

While it’s easy to pin all the blame for an unhealthy diet solely on one or two components such as sugar or saturated fat, the reality has many more shades of grey. When we focus too strongly on just one part of our diet, whether it be grains, sugar or kilojoule counts, it’s easy to miss the forest for the trees.