We all know that losing weight is difficult but keeping the weight off long-term is even tougher. My colleagues and I ran a study to see if intermittent fasting could be used to lose weight and then maintain that weight loss. The trial ran for one year and was divided into a 6-month weight loss phase followed by a 6-month weight maintenance phase. Participants in the intermittent fasting group consumed 500 calories on alternating fast days during the weight loss phase, and 1000 calories on alternating fast days during the weight maintenance phase.
At the end of the study, we found that intermittent fasting was indeed an effective strategy for maintaining weight loss! We were thrilled. The participants in the fasting group lost an average of 13 pounds in 6 months (ranging from 5 to 50 pounds: 10% of subjects lost 15 kg and above, 15% lost 10 kg and above, and 40% lost 5 kg and above) and they were able to keep all of that weight off by the end of the study. 80% of participants were able to maintain their weight for the duration of the study, I was so happy to find out that fasting could help people manage their weight long-term.
While running this study, several participants approached me asking for advice on how to deal with weight loss plateaus while fasting. Unfortunately, there is no ‘one size fits all’ remedy for this. However, I have found that incorporating an extra fast day into the week has helped some people breakthrough these plateaus. If that doesn’t work, I would also recommend increasing physical activity to 45 minutes per day (brisk walking is fine). These tricks have helped most people get past their plateaus and eventually start losing weight again.
During the study, we also found that certain groups of people lost more weight with intermittent fasting than others. For instance, we found that postmenopausal women did extremely well with this diet – they lost twice as much weight as premenopausal women after one year. Postmenopausal women lost 11 kg while premenopausal women lost 6 kg after 6 months of alternate day fasting. Amazing!
We also found that older men and women (50 years and over) had more weight loss success with intermittent fasting than younger adults. Older men and women (>50 years) lost 5 kg after 2 months of alternate day fasting compared to 2.5 kg by younger men and women (<50 years) (these are results from a shorter study.) Why is this? We are still not sure, but are currently conducting studies to figure this out.
As for next steps, I hope to run an even longer-term study (probably 2-3 years long) to see if intermittent fasting can help people manage certain obesity-related conditions, like type 2 diabetes and heart disease. I will be sure to share these findings with you as soon as they are published!
Maintain Your Goal Weight
These are Dr Varady’s top tips for maintaining your weight loss results:
- Gradually increase your calorie intake from 500 calories per day to 1000 calories per day on fast days (if you find yourself gaining weight, you can return to 500 calories per day)
- Remember, you still need to count calories on fast days!
- Move to incorporate strength building exercise, as well as cardio, into your workout (aim to exercise for at least 45 minutes a day, brisk walking is fine)
- Maintain your new weight with a good balance of protein, vegetables and wholegrains
- Watch less TV! I know it sounds strange, but while watching television we are bombarded with food commercials, which prompts us to snack more
- Weigh yourself at least once a week to catch any minor slip ups
- Don’t drink your calories! Certain beverages have the same caloric content as a meal (i.e. lattes that are actually milkshakes in disguise can pack in 600 kcal!) Quench your thirst by drinking clear fluids with no added sugar/fat
Right, let’s do this Master Fasters!