Kids, teens, and adults are usually bombarded with media messages about weight loss at the beginning of the new year. Many young athletes face a double helping of this pressure because weight loss and/or fat loss is often touted as a path to improved athletic performance. It’s important for parents and coaches to learn about some of the supplements kids may be tempted to use.
To be clear, there are no known dietary ingredients or supplement that measurably or consistently alter body composition or metabolism to result in loss of fat, or a change from fat to muscle. But there are several dietary ingredients that are often advertised to promote weight loss. In a 2006 study, it was revealed that 11% of US adolescents aged 14-19 have used weight loss supplements. However, weight loss products are fraught with false promises and health risks that should be evaluated seriously by parents and discussed with kids. Below is a table from a study published in 2003  listing ingredients that are commonly advertised in weight loss products.
|Ingredients commonly found in weight loss products||Actions (or advertised actions)|
|Ephedrine or pseudoephedrine (from ephedra [ma huang] or country mallow [Sida cordifolia]), caffeine, theophylline, theobromine (from cola nut, guarana, or mate), bitter orange (citrus aurauntium) Bladderwack (fucus vesiculosus), 7-keto-DHEA||Stimulants. Can interact with medications, caffeine in other foods and drinks, and come with all of the side effects of stimulants (restlessness, insomnia, racing heart, etc.)|
|Chromium picolinate, conjugated linoleic acid, carnitine, green tea, gymnem sylvestrea beta-hydroxymethybutryate, pyruvate, hydroxycitric acid (garcinia cambrogia), brindleberry||Often advertise to modify metabolism but with little to no proof|
|Ginkgo biloba, St John’s wort, Yohimbe||Often advertised to decrease stress- or depression-related eating, again with little to no proof|
|Soluble fibres (eg, glucomannan, psyllium, methylcellulose, pectin)||Advertised to make you feel full|
|Chitosan||Advertised to block the absorption of fat|
|Buckthorn bark and berry, Cascara sagrada bark,, flaxseed, manna, psyllium seed husk, rhuubard root, senna leaf and pod||Laxatives. Do not actually make you lose weight. Can cause side effects associated with laxative use (diarrhea, abdominal discomfort, bloating).|
Supplements marketed as “fat burners” are typically packed with stimulants, including (but not limited to) caffeine and the rest of the ingredients listed in the top row of the table above. While some of the ingredients in supplements marketed as fat burners may slightly increase lipolysis (the breakdown of fat), the primary effects of these supplements – and the primary dangers – are related to the stimulants.
1. Inadequate nutrition
Stimulants can temporarily enhance mental focus and the feeling of being “energized,” and thereby suppress appetite. This is the main way weight loss supplements promote caloric restriction, which then leads to weight loss. Significant caloric restriction can be particularly troublesome for kids and young athletes because it reduces intake of nutrients necessary to support growth, activity, and recovery. In addition to energy, kids get most of their vitamins and minerals from food. Weight loss supplements disrupt normal nutrient intake, which can leave kids low on calcium, iron, fat-soluble vitamins, and other important nutrients.