Yes, many bodybuilders eat junk food, but most do it strategically rather than recklessly. The approach varies widely depending on the individual, training phase, and dietary philosophy. Some follow strict “clean eating” plans that ban anything processed. Others use a flexible approach where foods like pizza, ice cream, or burgers fit into carefully tracked daily calorie and protein targets. The reality for most serious bodybuilders falls somewhere in between.
Flexible Dieting and “If It Fits Your Macros”
The most common framework bodybuilders use to include junk food is called flexible dieting, sometimes known as IIFYM (If It Fits Your Macros). The idea is simple: as long as you hit your daily targets for protein, carbohydrates, fats, and total calories, the specific foods you choose are secondary. Under this model, a bowl of cereal or a few cookies can coexist with chicken breast and broccoli in the same meal plan.
This isn’t just bro-science. A randomized controlled trial published in the Journal of the International Society of Sports Nutrition compared flexible and rigid dieting in resistance-trained individuals. Both groups lost the same amount of fat during the dieting phase. But in the weeks afterward, when participants returned to eating freely, the flexible group gained an average of 1.7 kg of fat-free mass (mostly muscle) while the rigid group actually lost 0.7 kg. Ninety-one percent of flexible dieters gained lean mass in that recovery period, compared to just 25% of strict dieters. The takeaway: allowing some dietary freedom didn’t hurt results and may have helped the body rebound more effectively.
A narrative review on bodybuilding nutrition echoed this, recommending a flexible dieting approach where no food or food group is eliminated. Competitors using flexible dieting were found to have fewer micronutrient deficiencies than those on traditional restrictive diets.
The 80/20 Rule in Practice
Most bodybuilders who include junk food follow some version of the 80/20 rule: roughly 80% of calories come from minimally processed, nutrient-dense foods, and the remaining 20% can come from whatever they want. In research settings, “unprocessed” foods are defined as those requiring one or two industrial processing steps at most, typically rated A or B on nutritional quality scales. “Processed” foods involve more manufacturing, tend to be higher in sugar and saturated fat, and contribute fewer vitamins and minerals per calorie.
That 20% buffer gives bodybuilders room for a dessert, a fast food meal, or a handful of candy without derailing their overall nutrition. The key is that the foundation of the diet still provides the fiber, vitamins, and minerals their training demands.
Why Food Quality Still Matters
Hitting your macro targets through mostly junk food is technically possible but comes with real costs. Your body burns significantly more calories digesting whole foods than processed ones. One study comparing matched meals found that whole-food meals produced a thermic effect of about 20% of the meal’s calories, while processed-food meals produced only about 11%. That’s nearly a 50% reduction in calories burned during digestion. Over weeks and months, that difference adds up, making it harder to stay lean on a processed-heavy diet even if total calories look the same on paper.
Micronutrient gaps are the other major concern. Athletes who rely too heavily on processed foods risk falling short on vitamin D, calcium, iron, zinc, and B vitamins. These aren’t abstract concerns. Iron deficiency impairs endurance and training adaptation. Low vitamin D weakens muscle power, increases injury risk, and raises the chance of stress fractures. Zinc deficiency reduces endurance and delays fatigue recovery. A diet built around pop tarts and protein shakes might check the macro boxes but leave your body short on what it needs to actually perform and recover.
Dirty Bulking: When Junk Food Takes Over
“Dirty bulking” is the term for eating large amounts of calorie-dense junk food to gain weight as fast as possible during the muscle-building phase. It’s popular because it’s easy and enjoyable, but the numbers tell a harsh story. Across more than a dozen overfeeding studies, 50% to 83% of weight gained during a caloric surplus came from body fat rather than muscle. In one study using fast food as the primary calorie source, 58% of weight gained was fat. In another using ice cream and candy bars, that figure jumped to 83%.
The damage goes beyond the mirror. Overfeeding studies have shown liver fat more than doubling (from 1.1% to 2.8%) in just weeks of surplus eating. High fructose intake, common in sodas and sweets, increased fat production in the liver by 83% and reduced insulin sensitivity by 17%. For a bodybuilder planning to eventually diet down for a show or a lean physique, dirty bulking means more fat to lose later with no extra muscle to show for it.
Post-Workout: The One Time Simple Sugars Help
There is one scenario where bodybuilders intentionally reach for sugary, “junky” carbohydrates: immediately after training. Resistance exercise depletes glycogen (the stored carbohydrate in your muscles) and creates a window where your muscles are primed to absorb glucose. Consuming high-glycemic carbohydrates after lifting spikes insulin, which accelerates glycogen replenishment and stimulates muscle-building pathways. Skeletal muscles absorb more than 80% of the glucose that insulin clears from your blood, and resistance training improves how efficiently those muscles respond to insulin.
This is why you’ll see bodybuilders eating gummy bears, white rice, or sugary cereal after a workout. In that specific context, fast-digesting carbs serve a functional purpose. It’s not a free pass for the rest of the day, but it’s one of the reasons bodybuilders can get away with foods that would seem counterproductive in other contexts.
Off-Season vs. Contest Prep
How much junk food a bodybuilder eats depends heavily on where they are in their training cycle. During the off-season (the muscle-building phase), calorie targets are higher, sometimes 3,500 to 5,000 calories per day depending on body size. That higher calorie allotment naturally creates more room for treats while still meeting micronutrient needs through whole foods. Most bodybuilders are more relaxed about food choices in the off-season, and this is when you’re most likely to see them eating burgers, pizza, or dessert regularly.
During contest preparation, when the goal shifts to losing fat while preserving as much muscle as possible, calories drop significantly. With fewer calories to work with, every food choice needs to pull more nutritional weight. Many competitors tighten up their food selection during this phase, though those using flexible dieting still include small portions of “fun” foods to stay psychologically stable through months of restriction. Studies have noted that even during contest prep, flexible dieters maintain better micronutrient profiles than those following rigid food lists.
The Psychological Side of Strict Dieting
One reason bodybuilders deliberately include junk food is to protect their mental health. Rigid dieting, where entire food groups are labeled “off limits,” is associated with higher rates of disordered eating behaviors. Research on collegiate athletes found that nearly 20% reported using pathogenic weight-control behaviors like binge eating, purging, or excessive exercise. Athletes at risk for orthorexia (an obsessive fixation on “clean” eating) had a 20.6% greater chance of also being at risk for a clinical eating disorder.
Bodybuilding already requires an unusual level of attention to food. Adding absolute food rules on top of that can push some people toward a harmful relationship with eating. Including moderate amounts of less “perfect” food helps many bodybuilders maintain a sustainable, long-term approach without the binge-restrict cycles that rigid dieting often triggers.