By Terri Chrisman M.Nutr, Dip.ACLM from the PAN Academy – our online learning platform where you can learn all about nutrition and health.

The world is overweight

A sad and shocking statistic from the World Obesity Atlas 2023 reveals that 2.6 billion people are overweight and 1 billion of those are obese. By 2035 these numbers are expected to double – representing over 50% of the world’s population of people over 5 years old. Even more startling is that by 2035, 20% of children over five years old will be obese (1).

We spend over 250 billion US dollars per year on diet books, pills and potions, yet, as a species, humans are getting fatter and fatter.

In this article, we are going to dispel the myths surrounding weight gain and weight loss. We will show you a simple strategy that will help you shed excess pounds and keep them off for the rest of your life.

Being overweight or obese is measured by body mass index or BMI. BMI is a population measure of fatness and is used to determine the risk of non-communicable diseases such as diabetes, heart disease, and some cancers (2).

But it’s not perfect. BMI does not consider muscle mass. Sometimes fit and muscular people have a high BMI due to the bulk of their muscle mass. Compared to a sedentary person with an unhealthy lifestyle, a fit person would be less at risk of disease.

Work out your BMI

Divide your weight in kilograms by your height in meters squared.

For example: I’m 65 kg and I am 1.73 m tall. My BMI is 65÷(1.73 x 1.73) = 21.7

See the image below for what category you fit into. If you are not in the normal range – read on.

How did we get here?

Why are we getting fatter? Is it genetics? Is it what we eat? Or something else?

It’s all those things and more.

Genetics do play a part in a person’s susceptibility towards obesity. Some people are more at risk of developing obesity than others, but that does not mean that they are destined to struggle with their weight. The fat mass and obesity-associated gene (FTO) is one of many genes that, when activated, can make you more susceptible to becoming obese. But just because you carry the gene, does not mean you are fated to an obese future.

Epigenetics is the study of how genes interact with the environment. What this means is, if you carry the FTO gene, for example, but you live a healthy, active lifestyle, the gene may not express itself, and you will remain slim. But if you are sedentary or have a poor diet, you will be even more susceptible to obesity than someone with the same lifestyle but without the gene.

In a nutshell, you can override your family’s ‘fat genes’ by taking control of your health. There are many other reasons why we put on excess weight. Some of them are out of our control.

• Low socio-economic status is positively correlated with obesity. If you are unemployed, less educated, from a minority population or a financially insecure woman, you have a greater risk of being obese (3).

• Food companies intentionally create addictive foods. The ‘bliss point’ is when a food has a precise combination of sugar, fat and salt to fire up the dopamine (feel-good hormone) receptors in the brain. This is why you can’t eat just one potato chip.

• Restaurants serve food high in fat, salt and sugar to keep you coming back. Unhealthy food tastes delicious!

The malnutrition paradox

We usually associate malnutrition with thinness. Now malnutrition is affecting the obese population. To understand this paradox, we need to revisit nutrition basics. The three macronutrients are protein, carbohydrates, and fat. The macronutrients have calories. Micronutrients include vitamins, minerals, phytochemicals, and antioxidants. Micronutrients have no calories. Being malnourished and obese means consuming too many macronutrients but not enough micronutrients (4).

Ultra-processed and fast food usually has lots of macronutrients but is often lacking in micronutrients. Eating processed and fast food can cause the body to crave more food – leading to excess calorie intake and further fat storage.

What is the secret to effortless weight loss?

Excess body fat is not benign. It creates systemic metabolic disturbances that can lead to diabetes, cardiovascular disease and some cancers (2). The great news is that returning to a normal BMI may lessen or even reverse these complications.

But how do we do that? The answer is simpler than you may expect.

Studies have shown that a whole food plant-based diet is more effective at weight loss than standard care practices. For example, researchers put one group of people on a low-fat vegan diet and another group on the American Diabetes Association (ADA) diet. Over a 22-week period, those on the vegan diet lost twice as much weight as those on the ADA diet (5).

In addition, the Adventist Health Study-2 of over 60,000 people found that vegetarians are about 30 pounds lighter than non-vegetarians of the same age and height (6).

Why is this so? It all comes down to calorie density.

Whole plant foods have low-calorie densities. This means the calories in the food are low for a given weight. Processed foods and animal products have high-calorie densities. It stands to reason that if you eat a lot of high-calorie dense foods, you will overeat calories and put on weight. But if you eat primarily low-calorie dense foods, you will eat fewer calories and potentially lose weight.

In 1983, scientists put this theory to the test. They had study participants eat as much low-calorie dense food as they wanted. Other participants ate as much high-calorie dense food as they wanted. Those who ate the low-density diet ate half as many calories (1500 calories per day) as those who ate the high-calorie diet (3000 calories per day), even though both groups ate the same volume of food (7). It is easy to see which diet would facilitate weight loss.

An added benefit is that low-calorie dense whole plant foods are high in micronutrients, such as antioxidants, water, and fibre – all of which are calorie-free.

How can this work for me?

Some people can change their eating habits overnight. For others, change is achieved in incremental steps. However you choose to change, adding more plant foods to your diet is a step in the right direction.

The image below gives examples of foods that have low-calorie densities and foods with high-calorie densities.

Notice how the foods with low-calorie densities are all whole plant foods and the foods with high-calorie densities are processed foods, fast foods and animal products.

If you or a loved one are trying to lose weight, please be kind to yourself. You will not always get it right. You may slip up and eat unhealthy food. That’s OK. It’s all a part of lasting change.

Don’t dwell on the mishaps. Focus more on all the healthy changes you are making each day. To get started, we have provided you with some tips on how you can improve the quality of your diet and improve your health for good.

Practical tips for you

1. Write a list of all the plant foods you already like. You may be surprised at how long the list is.

2. Add a new plant to the list every week. Explore new foods. Some you will like, others, not so much.

3. Write a list of all your favourite meals and then find ways to ‘plantify’ them. For example: swap out the beef for lentils in spaghetti bolognese.

4. Keep fresh fruit and chopped vegetables in easy reach for quick snacks on the go.

5. Bake, steam, grill or air-fry instead of using oil. Oil is the highest calorie-density food.

6. Don’t give up. Every unprocessed plant food you eat is improving your health.

Additional Information: