https://www.healthline.com/nutrition/whole-vs-skim-milk

Recent studies suggest that skim milk may not always be the healthiest option when it comes to milk. Omega-3 fatty acids have been linked to many health benefits, including improved heart and brain health and a lower risk of cancer. The more fat a cup of milk has in it, the higher it’s omega-3 content.  In the past, whole milk was considered to be unhealthy because of it’s saturated fat content, but recent research does not support this recommendation.  There is no solid evidence that saturated fat increases the risk of heart disease. Saturated fat does increase LDL, but not the most damaging type of LDL. It also raises good HDL levels.  Many people avoid drinking whole milk because they assume the extra fat and calories will cause them to gain weight.  Interestingly, the opposite is probably true. Many studies have shown that consuming high-fat dairy products, such as whole milk, may actually help prevent weight gain.  People who drink whole milk tend to weigh less. There is no evidence that drinking whole milk instead of skim will make you gain weight.  The recommendation to avoid whole milk may have been popular in the past, but it isn't supported by science.  Switching to whole milk in moderation may help you manage your weight over time.