We all have foods we rely on after a rough day, like indulgent mac and cheese or chocolate peanut butter desserts. But according to Rachel Kelly, author of The Happiness Diet (Atria Books), these foods could actually be doing us more harm than good.

Kelly began to think more about how the meals she eats affect her mental health when she visited the doctor five years ago, worried about her persistent anxiety. “[A]s I left she asked if had I thought about happy foods,” she told us. “She said to eat more oily fish, green leafy vegetables, and — nice one — more dark chocolate. I began to introduce more of these foods and began to feel calmer and happier.”

Kelly co-wrote the book, which references more than 150 scientific studies, with nutritional therapist Alice Mackintosh. See their tips for eating “good mood foods” — and avoiding ones that might have a negative effect on your emotions — below.

Foods to Avoid

Diet Drinks

Kelly says that reaching for that caffeinated soda in the afternoon is pretty much a no-no. “Aspartame, the artificial sweetener in many colas, contains an amino acid called phenylalanine. In some scientific studies, phenylalanine has been shown to hinder our production of serotonin (the happy neurotransmitter that regulates mood),” Kelly said, meaning the thing you’re trying to get a pick-me-up from could actually be bringing you down.

Fast Food

You probably saw this coming, but most fast foods also have ingredients that are bad for our mental well-being. “That order of XL fries is rich in trans fats. The partially hydrogenated oils extend the shelf life of most fast foods but also disturb your balance of omega-3s. Research from the University of Pittsburgh Medical Centre suggests that low levels of the fatty acid are associated with pessimism, depression, and aggression,” Kelly shared.


And, of course, refined sugar should be consumed very sparingly. “Relying on sugary foods like chocolate, candy, sweet breakfast cereals, and snack bars can also affect our mood by playing merry havoc with our blood sugar levels,” Kelly said. “These in turn feed through to mood swings: an initial high, but then a low.”

What to Eat Instead

If you’re craving soda because you want an energy boost, try whipping up a smoothie instead. Kelly recommends including bananas, pumpkin seeds, yogurt, and cacao to give your body a balance of healthy fats, proteins, vitamins, and minerals that will keep your blood sugar level steady, along with your mood.

For a quick snack, try almonds. “One portion or a good handful contains around 80 mg of magnesium, an essential nutrient that is calming to the brain and may help alleviate anxiety,” she told us.

And instead of picking up fast food, cook some make-ahead meals at the beginning of the week. She recommends healthy soups, stews, and curries, which can last for several days in the fridge so you can help yourself to a serving when hunger strikes.

Foods to Add to Your Diet

Once you get to the grocery store, it’s easy to be overwhelmed by the walls of ingredients and end up opting for your usual standards. But Kelly has some advice on what you can easily add to your diet for the biggest good mood impact.

“The single top foods we need to incorporate more of are those which contain omega-3s or the healthy fats,” she said. Examples include salmon, fresh tuna, and anchovies, and if you don’t eat meat, you can opt for flax seed, spirulina, walnuts, and leafy green veggies.

She also recommends foods high in zinc, magnesium, B vitamins, vitamin C, and folic acid, like nuts and seeds, chickpeas, sweet potato, lean red meat, and raw sauerkraut.

Mood-Boosting Snacks

For an in-between-meals mood boost try the following:

  • homemade granola
  • oat crackers with almond butter and banana
  • green beans
  • broccoli with hummus
  • green smoothie with avocado and banana
  • yogurt with cinnamon
  • yogurt with nuts and seeds

“I see food as my friend, in all its glory and variety,” she told us. Her book, she says, “is not about denial, it’s about introducing more variety into your diet and eating with focus and pleasure, and enjoying the foods that are scientifically proven to boost your mood.”

The Happiness Diet is available now on Amazon. In the meantime, you can try a recipe from the book below.

Dark Chocolate Brazil Nut Brownies recipe

We spent ages perfecting these, ensuring that they were soft, rich, and gooey in the center. Though they are still a treat, you have more control over the ingredients when you are making them yourself. Spelt flour is whole-grain, meaning that it won’t lead to a sugar spike as white flour does, and Brazil nuts contain selenium, which, as we have seen, plays an important role in the immune system. Cacao is a rich source of magnesium and antioxidants.


  • 10 Brazil nuts
  • 4 ounces dark chocolate (ideally 100% cocoa, or use 85%)
  • ½ cup almond milk
  • ⅔ cup coconut oil, plus extra for greasing the pan
  • 1 cup maple syrup
  • seeds from ½ vanilla bean or 1 Tablespoon vanilla extract
  • 2 ounces raw cacao powder, sifted
  • 3 eggs
  • ¾ cup plus 1 Tablespoon spelt flour
  • 1 teaspoon baking powder
  1. Preheat the oven to 375 degrees Fahrenheit. Grease a 12 x 8-inch brownie pan and line it with parchment paper. Leave the paper sticking up at the sides to make it easier to lift the brownies out when they are cooked.
  2. Roast the Brazil nuts in the oven for 15 minutes, turning them once halfway through. They should be slightly browned. Let them cool, and then chop them coarsely.
  3. Put the chocolate, almond milk, coconut oil, maple syrup, and vanilla seeds or extract in a saucepan over very gentle heat, stirring regularly, until everything has melted and you have a rich, glossy-looking batter.
  4. Remove the pan from the heat and whisk in the cacao powder.
  5. Allow the mixture to cool for 10-15 minutes, and then beat in the eggs. Add the flour, baking powder, and chopped Brazil nuts.
  6. Pour the mixture into the prepared pan and bake it in the oven for about 12 minutes. Insert a toothpick; it should come out with a little chocolate residue. If you like your brownies less gooey, put the pan back in the oven for 3-5 minutes, but take it out before the top starts to crack, otherwise the consistency will be more like cake.
  7. Remove the pan from the oven and use the baking paper to help you slide the whole brownie onto a cooling rack. Cut it into squares once it has cooled completely. Makes about 15 squares.

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