New research reveals the serious risks of yo-yo dieting. In this study yo-yo dieting was shown to impact kidney and heart function.

Between 2017 and 2018, 73.6%  of adults ages 20 and over in the United States had overweight or obesity. Having overweight or obesity is a major health concern as it increases one’s risk of conditions including:

  • Type 2 diabetes
  • Coronary Heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis
  • Sleep apnea

Weight cycling or “yo-yo dieting” happens when people intentionally lose and regain at least 5 kilograms (kg) on three occasions or more. Estimates say that between 10% and 30%  of men and women have tried this kind of dieting before.

While losing weight can positively impact health, studies show that yo-yo dieting negatively impacts cardiovascular health as it causes factors including blood pressure and glucose levels to fluctuate.

Study on Risks of Yo-Yo Dieting

In a recent study, researchers studied the effects of yo-yo dieting with severe food restriction in rats. They found that rats who underwent yo-yo dieting had reduced heart and kidney function after three dieting cycles despite “looking” healthy.

  • For the study, the researchers divided 16 rats into two groups.
  • One group was fed a 60% reduced-calorie diet for 2 weeks followed by a 3-week period of weight regain for three cycles to simulate yo-yo dieting.
  • The other group was kept as a control.
  • Throughout the study, the researchers assessed the rats’ cardiac and renal functioning via ultrasound. They also tracked their insulin sensitivity via blood tests.
  • After the first reduced-calorie period, the rats lost 20% of their body weight, however, this was regained during the ensuing 3-week refeeding period. The rats then lost 20% and 19% of their body weight over the next two periods of restricted calorie intake.

Results of Study on Risks of Yo-Yo Dieting

The researchers noted that, at the end of the study, rats on a reduced-calorie diet experienced 20–40% reductions in renal artery flow and cardiac output. They were also more insulin resistant, which is a risk factor for diabetes.

When asked what may explain the findings, Aline M. A. de Souza, Ph.D., Assistant Professor in the Department of Medicine at Georgetown University Medical Center, one of the study’s authors, told MNT:

  • “We saw that after 3 cycles of a very restrictive diet the heart was ejecting less blood, and this means less blood going to the kidney.
  • The body is very flexible and it tends to adjust but if it’s a chronic situation some organs can lose the adjustment ability.
  • This is one explanation; we still need to investigate other reasons.”

The researchers concluded that people who intentionally or unintentionally engage in yo-yo dieting may be at an increased risk of developing cardiometabolic disease.

Click here to read more about the risks of yo-yo dieting.