This might be dumbing it down too much, but processed foods lead to inflammation whereas whole foods like fruits, vegetables, and whole grains are anti-inflammatory. Inflammatory disease can run rampant in your system, making it impossible to lose weight even when dieting.
Exercise can even cause acute inflammation. While this only lasts a short time and is normal, the right diet can help keep it under control. A poor diet, however, can result in chronic inflammation. Stress and over-exercising can also lead to chronic inflammation. The combination of these things puts you at risk.
Injury and Illness
Inflammation is the body trying to protect itself. Long-term inflammation can lead to several diseases and conditions including some cancers, rheumatoid arthritis, periodontitis, and heart disease. When vascular or muscular tissue swells to protect itself, it also risks slowing down specific processes.