Basal Metabolic Rate
Even when you aren’t exercising, your body is consuming energy. The amount of calories your body burns each day just to sustain itself is called your basal metabolic rate (BMR for short). When in ketosis, eating fewer calories than your BMR will stimulate healthy weight loss as your body will get the extra calories it needs from body fat.
However, your BMR is not fixed. A low BMR can make weight loss especially challenging, especially since eating fewer calories can actually slow your metabolism down — a survival mechanism meant to store energy when food is scarce. A low BMR might also contribute to your body weight set point, a weight at which you’ll experience a stall no matter how high your ketone level or how strictly you follow your macros. It happens at different weights for different people and takes a lot of work and patience to break through.
BMR, set points, and insulin
Though insulin’s primary function is to process the sugar in your blood, it is also involved in the metabolism of protein and fat as well and gets produced in small amounts when you eat, no matter what you eat. It also regulates how much of what you eat gets stored as fat instead of burned for energy. The higher your insulin levels, the more energy you store and the less you burn — effectively lowering your BMR and reinforcing your set point. For those with elevated insulin responses, the extra insulin that your body produces only worsens the effect.
Healing your BMR and breaking through your set point involves keeping your insulin levels in check. Getting them down to a healthy baseline can give your body the ‘reset’ it needs.
Healing your BMR
Because all foods affect insulin levels to some degree, the best way to control them is through intermittent fasting and fat fasting. Fasting doesn’t necessarily mean that you refrain from eating altogether; it can also mean significantly restricting your daily calorie intake, providing a shock to the system that can boost metabolism.
However, not all fasts are the same: a high-carb fast will keep insulin levels high and prevent ketosis, which could lead to a negative impact on your BMR while also burning muscle and organ tissue for energy instead of your body fat. A high-fat fast, though, does the opposite: it dramatically reduces your insulin levels while burning your body fat and the fat in your diet for fuel, promoting healthy weight loss.
Intermittent fasting (IF) means restricting your eating to certain times of the day while maintaining your usual ketogenic macros. IF can take different forms: the 16/8 fast involves fasting daily for 16 hours (usually skipping breakfast) and eating during the remaining 8; the eat-stop-eat fast involves fasting for one or two days a week (not consecutive, though!) and eating normally for the remainder. Once your body adapts to IF, you will experience lessened hunger and cravings, meaning you’ll eat less often and feel more satiated after meals.
Fat fasting, where calories, protein, and carbs are reduced while fat is increased, forces the body to switch to burning fat for energy instead of glucose. This usually works out to about 1000–1200 calories a day with 80–90% coming from fat. Fat fasting is great for kick-starting ketosis, but should only be done occasionally and for limited periods because of the restricted protein intake.
If you are interested in either fat fasting or intermittent fasting, ask us for a protocol in your daily logs or by email.
While it technically doesn’t increase your BMR, increasing your physical activity can increase your daily calorie needs since your body is using extra energy for the exercise. The more regularly you exercise, the stronger and more long-lasting the effect. However, increasing your muscle mass will increase your BMR since muscle tissue is very metabolically active. Incorporating resistance training into your exercise routine can give your BMR the boost it needs to help with weight loss.