What makes junk food unhealthy?

When you think of junk food, you usually think of a particular food and the momentary pleasure it gives you when it reaches your lips. While these moments of indulgence can satisfy a craving, it’s important to understand how certain ingredients found in your favorite junk foods can increase your risk of illness and chronic disease when eaten regularly.

What’s more, they can interfere with some key processes that we as athletes need to maintain optimal body function impacting your performance, recovery, and overall health.

In this article, we’ll take a look at what junk food is, how it affects your health and performance, and what you can do to help limit your consumption. First, let’s break down what makes junk food unhealthy.

When food is processed, it is changed from its natural state with additives, preservatives, or artificial ingredients. These changes can make the food more appealing and taste better but also make it harder for the body to digest, especially as they are low in fiber.

A diet that is lacking in fiber can cause several unwanted symptoms that put a wrench in your training or competitions, like:

• Bloating
• Constipation
• Weight gain
• Fatigue
• Inflammation
• Low mood
• Poor heart health⁶

You’ve probably heard that junk foods are empty calories. This is because they can provide a burst of short-lived energy but offer little nutrition.

Most junk foods are high in sugar, unhealthy fats, or refined carbohydrates, leading to energy spikes, but lack the vitamins, minerals, and fiber your body needs to meet its demands. And these energy crashes can have a detrimental effect on your endurance and recovery.

Let’s break it down: when you eat a high-sugar or high-fat snack, blood sugar levels can rise rapidly. This triggers the body to produce a large amount of insulin. A rapid drop in blood sugar follows, causing an energy crash, quickly making you hungry and craving something sweet to increase your sugar levels. This kickstarts the process again.

Having a drop in blood sugar is totally normal and healthy. However, junk food can cause the body to overreact, leading to negative side effects.

When food is processed to improve shelf life, it often loses essential nutrients such as vitamins, minerals, and antioxidants — nutrients your body needs to repair tissue, boost immunity, and produce energy.

Without these nutrients, your body struggles to meet the demands of exercise and maintain overall health. A diet high in junk food can lead to nutrient deficiencies that not only slow muscle recovery but also weaken joints and connective tissue, increasing the risk of injury and illness.

Choosing nutrient-dense foods is the best way to support your body’s needs and stay on track to achieve your fitness goals.

Junk foods are known for being high in sodium and salt. Eating a diet high in salt increases your risk of high blood pressure, heart attacks, and strokes.¹ It can also lead to dehydration, which as we all know, hydration is fundamental for all athletes.

Sodium is an important part of rehydrating following exercise.² However, consuming too much salt or sodium within your overall diet can upset the hydration balance in the body, leading to muscle cramps, reduced endurance, and fatigue.³

Refined sugars have been stripped of beneficial nutrients during processing, leaving nothing but sweetness. This type of sugar, like white sugar, can cause insulin spikes and contribute to weight gain.⁴

Eating a lot of sugar regularly can make fat cells less responsive to insulin, increasing the risk of insulin resistance and developing type 2 diabetes. However, people who keep their added sugar intake below 5% of their total calories experience a 50% reduction in the likelihood of prediabetes or type 2 diabetes.⁵

For athletes, eating a lot of high-sugar foods can interfere with how muscles store energy, which is important for endurance and performance. In general, athletes are able to replenish their muscle energy quickly after exercise because their bodies absorb sugar from the blood easily.

But eating too much refined sugar over time can make the body less responsive to insulin, the hormone that helps move sugar into muscles. This makes it harder for muscles to store energy, which can hurt stamina and slow down recovery.

Many junk foods are rich in unhealthy fats like trans fats and saturated fats, which can raise bad cholesterol or low-density lipoproteins (LDL) in the blood while lowering good cholesterol. Over time, this increases the risk of heart disease and blocked arteries.

Athletes report that eating foods high in fat or sugar makes them feel lethargic, affects their physical performance, and could contribute to weight gain.⁷

We’ve all experienced it – just one more chip, one last spoon full of ice cream. But what is it that makes junk food so difficult to resist?

You can thank the fat, sugar, and salt content in junk food for that. These ingredients play right into the reward and pleasure systems in the brain. When you eat junk food, your brain releases dopamine, a neurotransmitter or “happy chemical” that makes you crave more unhealthy foods. And so, you reach for that chip.

Junk foods have been designed to be highly palatable and engineered to taste good. They often bypass the body’s internal systems that make you feel full, leading to overeating and unhealthy food cravings. Your brain can become conditioned to craving these foods, which can cause a similar effect to other addictive substances.⁸

The table below lists some of the short-term effects that regularly eating junk food can have on the body and how they can snowball into long-term consequences.

Unhealthy foods, particularly those high in sugar and fat, can have a negative impact on mental health. They cause excessive blood sugar fluctuations, leading to mood changes, irritability, and tiredness.

Research has shown that regularly eating junk foods increases the risk of developing depression⁹ and psychological stress.¹⁰

The lack of important brain-boosting nutrients, including antioxidants and omega-3 fatty acids, may disrupt cognitive function and emotional well-being. For example, a low dietary intake of omega-3s is associated with an increased risk of dementia and cognitive decline.¹¹

Junk foods change inflammatory pathways in the body, increasing oxidative stress and inflammation-related biomarkers. These biological changes can be linked to the development of mental health disorders and negatively impact training and physical performance.

Here are six ways you can cut down your junk food consumption and promote healthier choices:

1. Meal prep: Preparing meals and snacks in advance will lower the temptation to grab unhealthy and convenient options when you’re hungry or pressed for time. Bonus – it can also save you money!
2. Make healthy swaps: Swap out unhealthy snacks for healthier, nutrient-dense options like fruits, nuts, wholegrain crackers, and raw veggies. Have them prepared and accessible so sugary alternatives don’t tempt you.
3. Get hydrated: If you’re craving something unhealthy, try drinking some water. Drinking enough fluid can temporarily curb your snack attacks by filling up your stomach until you find a healthier alternative.
4. Prioritize protein: Include a mix of high-quality protein sources, like lean meat, poultry, tofu, and edamame, rather than high-calorie burgers or fried chicken. Eating high-quality proteins will keep you fuller for longer, limit obesity, and improve athletic performance and recovery.
5. Catch some zzz’s: A bad night’s sleep can leave you craving junk food, fooling you into thinking it will give you an instant energy boost. Rock your night-time routine by incorporating some key sleep strategies. Better sleep will prompt you to make healthy food choices, and the positive cycle will continue.
6. Choose healthy fats: Not all fats are bad – that’s simply a myth. Trans and saturated fats should be limited, but healthy fats, like those found in vegetable oils, avocadoes, and oily fish, are part of a healthy diet and should be consumed regularly. Fatty foods are best avoided a few hours before and after exercise because they slow digestion.

Junk foods are tasty and can even feel addictive, but they also come with some pretty harmful side effects that can hinder your athletic performance and prove detrimental to your overall health when consumed regularly.

And while we’re all about enjoying life (and maybe a piece of cake or two), it’s incredibly important to strike a balance with a nutrient-rich diet that incorporates vitamins, minerals, and antioxidants.

Eating healthier doesn’t require an “all or nothing” mentality. Make simple healthy swaps and small lifestyle changes to limit junk food. Every action you take will help you reach your goals faster and keep you locked in the fitness game for the long haul.