fredag 4 januari 2013

Över och undervikt

De vetenskapliga hälsorapporterna tycks dugga allt tätare. Senast gällde det en metastudie som jämförde överviktiga med icke-överviktiga (som jag förstår det: BMI övervikt mot normal- och undervikt). Undersökningen är säkert korrekt i ett stort statistiskt perspektiv, men den enskilde med ett MBI på 24 bör not inte äta mer socker för att gå upp i vikt. Här är en artikel som ger alternativa förklaringsmodeller till resultatet. Jag tycker framför allt att följande argument övertygar:

2. Death risk is the wrong standard. So what if fat doesn’t correlate with mortality? It still correlates with many diseases, which may ultimately affect mortality. Some studies covered by the JAMA review tracked people for up to 15 years. Others tracked them for as few as five years. Anyone who made it to that point counted as a survivor, regardless of diabetes, heart disease, or other conditions that may have contributed to death after the study ended.
5. Some kinds of fat are worse than others. At the moment, scientists seem to agree that while belly fat is bad for you, butt and thigh fat might be safe or even beneficial. So instead of focusing on BMI, we should measure your waist-to-hip ratio, body-fat percentage, blood pressure, blood lipids, glucose, and cardio-respiratory fitness.
12. Overweight doesn’t mean you’re getting fat. It means you’re resisting obesity. "In a society prone to both epidemic and increasingly severe obesity, it may be that those who manage to remain in the 'overweight' class are, in fact, those who are actually doing quite well," says David Katz, director of Yale’s Prevention Research Center. So instead of seeing these people as formerly thin folks with bad habits, we should see them as fat-prone folks with good habits. How this squares with the notion of overweight as a gateway to obesity—a warning echoed by Katz—isn’t clear.
Frågan är dock hur stor statiskt roll den här listan spelar.

Inga kommentarer:

Skicka en kommentar