As bad as a lack of exercise is to the body, the million-dollar question is if a bad diet causes more disease and illness than being lazy and sedentary.

Both are horrendous to the body: lack of exercise and a lot of junk food intake.

Of course, it’s better to be physically trained if you’re on a junk food diet than it is to have an untrained, flabby body — especially an overweight one — all while eating a lot of sugary, highly processed foods.

“To keep your body as healthy as possible, you need a good diet and regular exercise,” says Sara Artigues, a registered dietician and certified personal trainer out of New Orleans.

“They go hand in hand. However, breaking down the two of them, a poor diet can lead to obesity and disease much quicker than a lack of exercise.

“A diet consisting of mostly junk food, such as sugars and processed/high sodium carbs, can lead to obesity, even if you’re getting some form of exercise.

“While exercise is great for helping prevent cardiovascular disease and type 2 diabetes, if you don’t have a nutritious diet, you’re not going to reap all of the benefits that exercise offers.

Out-Training Poor Nutrition

“Many believe that they can eat junk food and then just go burn it off at the gym,” says Artigues.

“While yes, exercising is great for burning calories — if you’re constantly feeding your body damaging foods, there’s only so much that exercising can do.

“Even the most physically fit people will suffer from the effects of a poor diet.”

This may be the case for those “thin fit people who work out all the time” who develop cardiovascular disease or cancer – the very individuals whom some obese people point out when trying to convince others that one can be fat but still healthy.

If someone’s been exercising hard for years, staying lean all throughout, but then has a heart attack – this does not mean that very obese people can be healthy.

A fair conclusion is that quite possibly, the unlucky individual had a chronic junk food diet.

“If you want to stay in shape and help prevent obesity and other diseases, you cannot just exercise alone,” continues Artigues.

“You have to make ideal choices in what you put in your body on a fairly consistent basis while also staying active.”

What a Study Says About Diet vs. Exercise for Causing Disease and Obesity

A report in the British Medical Journal says that a bad diet is far worse, causing more obesity, than is a lack of exercise. And obesity leads to all sorts of disease.

The BMJ editorial, chiefly written in 2017 by Dr. Aseem Malhotra, a UK cardiologist, does point out that regular exercise “reduces the risk of cardiovascular disease, type 2 diabetes, dementia and some cancers by at least 30 percent.”

However, poor diet causes an even greater hit to the body. The editorial states that a processed food diet “generates more disease than physical inactivity, alcohol and smoking combined.”

Effect of Poor Diet on Thinner People

The editorial points out that “all sizes” are vulnerable to “lifestyle-related diseases.”

This includes the consumption of sugary soft drinks by non-overweight people.

The BMJ report insists that hard exercise cannot undo the harm of a poor diet.

The best way to end any confusion about whether a junk food diet causes more disease or obesity than does lack of exercise is to simply do two things: 1) Limit processed food, and 2) Take up aerobic and weight-bearing exercise.

Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  
Sara’s training services include fitness/body composition assessments, nutrition planning, customized programs and spin class instruction for a variety of clients. 


Top image: drobotdean