About diet variety

What? Isn’t variety good for your health? Dieticians and health guidelines tell you that if you are going to eat a large variety of different foods you are going to meet your nutritional needs. Well, that sounds reasonable but has also a dark side: the more variety we have in one meal, the more calories we are going to eat. Before explaining why this is the case and what can we do against it, let’s define some terms.

Dietary Variety

In one of my favourite papers on this topic, the authors describe four types of variety:

1. overall dietary variety: overall number of different items within a diet
2. meal variety: number of different items within a meal
3. food group variety: number of different items from a food group (i.e. high fat, high sugar snacks)
4. entrée variety: number of different main items (entrées) served at a meal across time

Sensory-specific satiation

Satiety is the feeling of being full after having eaten a meal and sensory-specific means that this fullness only applies to foods that have similar sensory properties (sweet, salty, sour, fatty) to the ones we just ate (from The Hungry Brain, Stephen Guyenet). What does this mean in practice? You have eaten a giant portion of sushi but you still have room for a matcha ice-cream (I am writing the blog post from Japan by the way 🙂 ). This is also called the “buffet effect”: we are eating something different with every bite, therefore our brain does not habituate to any particular food and in most cases we are going to overeat even if on most buffets the food is not particularly attractive.

Habituation

Habituation helps us to differentiate important information from unimportant noise: the more we’re exposed to a stimulus within a short period of time, the less we respond to it. What does it means in the context of eating and overeating? At some time you get bored of eating the same food and you feel satiated: that’s the phenomenon described above.  Interestingly, it seems that very little variation, like texture or color, is enough to break habituation. In a study, children where given pasta in a different form and they overate on pasta compared to the chicken nuggets control (no comments about the food choices for this study…).

Why did our brain evolve sensory-specific satiation?

The body has an interest to consume different foods because they (may) contain different nutrients. This was important in an environment where food was scarse in order to get as much vital nutrients as possible, but in our current western world where overabundance is the rule, it’s one of the reasons why the population is getting fatter. To cite Menno Henselmann‘s words during one of his talks: “Variety isn’t always good. Think of a supermarket. You have a high variety of junk food and a small variety of healthy food choices. If you pick a random choice of products, you will end up with a very unhealty high variety of foods.”

Practical aspects

How can you use this knowledge if you are trying to lose fat?

• reduce meal variety: especially if you are eating ad libitum (= without tracking calories and eating until satiated) keep it simple. Combine one protein source with fat and carbs and that’s it: for example you may have a steak with roasted veggies. If you are on a buffet try to limit yourself on a satisfiying portion of three of your favourite foods and stick to it.
• reduce food-group variety for high palatable food which is high in calories (because high in fat and carbs): chose one favourite treat that you really love, be very specific (i.e. not just “chocolate” but the 80% cocoa chocolate from Zotter) and fit just that one specific treat in your diet.
• it may not be necessary to reduce overall dietary variety but in my experience it may be helpful to do so in order to simplify your diet if you are in a caloric deficit. I had always the same delicious breakfast (my incredibly easy cheesecake) and I loved it. I didn’t have to think much about it and helped a lot increasing adherence and reducing decision fatigue. Some of our clients reported that for them it is not an option as they get bored soon but I really encourage you to give it a try. Try with your very favourite food and just vary one component: i.e. have always greek yoghurt with different fruits for breakfast.
• it is also not mandatory, but it is helpful to reduce your entrées to just one per meal: always having a soup before or a dessert after your main course obviously adds calories. If you really can’t live without it, try a calories-free/very-low calories option.

Did this blog post help you finding some additional points to stick better to your diet? Please let us know in the comment section below or share it with your friends and family. Please help us spread some beary wisdom, we would be very thankful!