Should you have Special K or sardines for breakfast?

I grew up in the 1980s when Special K cereal was the healthy breakfast that everyone was eating. I remember as a child watching the perfectly svelt and toned red swimsuit-clad woman, as she seductively ate her cereal, and I thought that must be the panacea of health. 

Fast forward 30 years and our understanding of low-fat foods are changing. The removal of fat from our diets may be contributing to ill-health rather than benefiting it. Here I will review a recent small but highly controlled study at the National Institutes of Health, examining the effects of a low-fat, plant-based diet vs a low carbohydrate, ketogenic, animal-based diet. The study reviewed the impact of hormone levels, body weight, and more.  

Which diet leads to higher calorie intake?

The debate around the health benefits of low-fat plant-based foods, vs a ketogenic-style diet, is a complex one. However, this study focused on whether the ketogenic diet or the effect of a low-fat diet on blood sugar and insulin spikes leads to hunger and overeating, resulting in greater calorie intake.

Interestingly, the results indicated that those on a low-fat diet ate 550 to 700 fewer calories, and lost a significant amount of body fat. People on both diets lost weight. There was no difference in hunger, feeling of fullness or enjoyment in the two diets. And even though, those on a ketogenic diet predominantly ate fat-based foods, they didn’t gain weight.

Both diets resulted in better-regulated blood sugar and insulin levels.

As blood sugar imbalance can lead to weight gain, metabolic syndrome and even diabetes, this a positive indication that either diet would benefit those who struggle with blood sugar issues. However, as this was a short term study over four weeks, it is not understood how these diets impact health if the diet was followed long term.

How does this help the debate?

The study results suggest that weight gain and overeating aren’t as simple as the number of macronutrients in your diet. It is more likely the result of the quality of the food you are eating, regardless of whether it contains carbohydrates or fats. Another earlier study showed that if you eat a highly-processed food diet, you are more likely to overeat and gain weight than a whole food diet.

As this study was conducted solely on understanding the effects of these diets on calorie intake, it does not consider the other health benefits of either diet. Besides, the impact of nutrition and diet is highly personalised based on your genetics, upbringing, environment, toxic burden and many other factors, so finding what works best for you might be different to the next person. 

This study further highlights the effect of diet and nutrition on human health. More reviews in a similar vein would be helpful to understand these complexities better in preventing disease.  

So, should you have Special K or sardines for breakfast? The choice is yours, but the sardines will have a higher nutrient value. And they are whole natural foods, rather than ultra-processed, so the decision is easy for me without considering macronutrient content.