A Biological Clock Gene Linked to Weight (PER2)

Take Care of Your Biological Clock (Circadian Rhythm)

A study that looked at brain function in 90 adolescents, found that those with the ‘C’ variant of rs2304672 who went to sleep later had reduced activity in the reward circuitry of the brain [R]. This means they may tend to favor short-term “rewarding” activities late in the day, such as browsing social media before going to bed or snacking.

To counteract this, you should take care of your biological clock by going to sleep earlier, at roughly the same time every day, and getting enough sleep on a daily basis. Avoid any distractions before going to bed that can potentially disrupt your daily rhythm.

Researchers over the past few decades have recognized the importance of circadian biology in obesity. It turns out that circadian biology may have a massive influence on energy balance and metabolism [R].

Both shift work and being exposed to bright light at night have been linked to an increased risk of obesity [R, R].

What’s the best way to shirt your biological clock?

Start by going outside in the morning [R, R]. A study in 54 people found that getting exposed to lots of light earlier in the day was associated with a lower BMI [R].

There are several other ways to improve and shift your circadian rhythm, including:

• eating earlier in the morning and restricting food at night
• getting more sunlight during the day [R, R, R, R]
• avoiding bright light at night and wearing blue blocking glasses at night [R, R, R] 
• going to bed and waking up at the same time [R]

You can find more information about resetting your circadian rhythm here.

The carriers of the ‘C’ allele may be more prone to engage in short-term “rewarding” activities that disrupt their circadian rhythm and their body weight, such as browsing social media before going to bed or snacking. Taking care of your biological clock is a good approach to weight loss, and it may counteract the effects of harmful variants in the PER2 gene.

Adopt Healthier Eating Behaviors

Carriers of the ‘C’ allele who are overweight may benefit from changing their behavior, by [R]: 

• Avoiding snacking
• Avoiding being around food when bored

Eat More Calories Earlier in the Day

The ‘C’ allele of rs2304672 has been associated with skipping breakfast [R].

Getting more calories in the morning has been linked to lower odds of being overweight or obese. On the other hand, eating more during nighttime increased those odds. Plus, eating later in the day was associated with losing less weight when dieting [R, R, R].

In animal studies, mice who ate at the wrong time gained more weight, despite having the same calorie intake and activity over the course of the experiment [R].

However, you need to be careful with adding breakfast to your routine. A large meta-analysis suggests that eating breakfast regularly only helps weight loss as a part of an overall healthier and more active lifestyle. If you don’t make changes to your other meals, you’d just be adding additional calories to your diet [R].

The carriers of the ‘C’ allele may benefit from avoiding snacking and being around food when bored. They can also benefit from eating more of their calories earlier in the day and not skipping breakfast.

Don’t Overdo Alcohol

A study that compared alcoholics with healthy people found that alcoholics had lower activity of circadian clock genes, including PER2 [R]. 

Lower PER2 activity in fat tissue has been linked with greater waist circumference in another human study [R].

Therefore you may benefit from avoiding alcohol or consuming it in moderation (1 glass per day or less). 

Chronic alcohol consumption can disrupt circadian genes, including PER2. 

Forskolin

Forskolin activates circadian clock genes, including PER2, in animal cells [R].

While there are no studies that confirm the same thing happens in humans, there are studies that show that forskolin may help with weight loss.

There are several promising small studies, involving 20-80 people, that suggest that forskolin may help prevent weight gain, improve weight loss, and decrease body fat [R, R, R, R, R, R].

Forskolin also destroyed fat in animal and cell-based studies [R, R, R, R].

However, bear in mind that although forskolin may help with weight loss, it’s unlikely to be effective without other measures such as doing more exercise and changing your diet. Discuss with your doctor if forskolin may be helpful in your case and carefully follow your doctor’s instructions.

Forskolin activates PER2 in animal cells and several studies suggest it has beneficial effects on weight loss in humans.