Nourishable digs into the clinical studies on Isagenix to figure out whether Isagenix works for weight loss. Subscribe to Nourishable at

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Isagenix is a multi-level marketing company that sells meal replacement shakes and supplements. Their 30 day weight loss system is described as a “cleansing and fat burning pak ideal for individuals who want to lose weight using a long-term, flexible program.” The website is full of anecdotes of weight loss success. Research: they recruited 43 healthy overweight or obese subjects. During the weight loss phase, all 43 subjects followed the Isagenix weight loss program. Breakfast and lunch were each replaced with 240 calorie IsaLean shakes, then they ate a low-cal dinner and an evening snack bar for a total of 1200-1500 calories 6 days/week. Intermittent fasting once per week with a cleansing beverage plus snacks for 400 calories. After 3 months they lost on average 10% of body weight. But there was no control group! The weight maintenance phase had serious design flaws. Subjects picked whether they wanted to follow the heart healthy diet or modified Isagenix. The heart healthy group was given recommendations for a high fiber, low cholesterol diet with 35% of calories fat and 50-60% carbs. The modified Isagenix group replaced 2 meals/day with shakes while consuming whole food for the rest, plus 1-2 days of intermittent fasting per month. In rigorous study design, it is important to randomize subjects to different treatments so the impact of the treatment can be isolated without confounding. Subjects self-selected which program they wanted to follow. Isagenix dieters maintained weight loss while heart healthy dieters regained weight. Not everyone was included in these results. They filtered out subjects who weren’t compliant with the program for the whole year. 47% of Isagenix dieters and 22% of heart healthy dieters were dropped. For weight maintenance, the most important question is whether habits can be sustained. They used some shady statistics (one-tailed t tests) to stack the deck. Isagenix may work if you stick with it perfectly, but only about 50% of people can. Other 3 month studies show that low calorie partial meal replacement programs can yield short term weight loss. It’s possible to follow any restrictive plan for a few months, but what about longer? The Look AHEAD study investigated an intensive lifestyle intervention. The counseling group lost significantly more weight. Researchers compared which strategies were used more frequently by the weight loss maintainers compared to the regainers over 8 years. There was no difference in meal replacements – but they reported more physical activity, weight monitoring and low calorie intake than the regainers. The National Weight Control Registry follows individuals who have maintained at least a 30 pound weight loss for a year or more. Only about 1/10 report using a meal replacement shake, whereas 9/10 keep healthy foods at home, regularly self weigh and physical activity. There is no magic bullet for weight maintenance, but the best data we have indicates that physical activity, weight self monitoring and consuming a reduced calorie diet are the most important strategies.