Weight loss is one of the most common nutrition goals amongst any population. The formula is basic that everyone has heard regarding eat less and move more for the calories in, calories out idea. But it isn’t talked about as much how the metabolism changes with weight loss. Those changes are why many tend to regain the weight they just lost.
How the metabolism changes
The body tries really hard to stay at its current weight. No matter if someone’s goal is weight loss or weight gain, the body fights it a little bit. Change is hard for everyone, our body’s included! Two hormones in particular drive this; leptin and ghrelin.
Leptin is what helps us to feel full. After a big meal, leptin levels increase and signal to the brain “ok, that’s enough” to stop eating. Ghrelin is the opposite and makes us feel hungry when we need to eat. Long periods without food, ghrelin levels increase until we eat something.
When losing weight, these signals get a little mixed up. To try and keep the body weight at the same level, leptin levels become reduced. The signal and how loud leptin is shouting that the body is full also decreases. These things result in feeling more hungry and thus eating more.
Rate of weight loss
How quickly someone loses weight can impact these effects. Slow and steady is the key. The faster weight is lost, the greater amount of that weight tends to be muscle. This obviously isn’t ideal! By going at a “slow” rate of around 0.5-1.0 pounds lost per week, that can be a great rate to preserve one’s muscle. That muscle is what will help to keep the metabolism burning to maintain the weight that is lost.
On the other hand losing weight quickly comes at the expense of muscle. The metabolism changes with that are that it begins to slow down. Ghrelin levels increase quite a bit as well which can lead to overeating or sometimes even binge eating. It’s a recipe for potential disaster. This is a big reason why many people who regain their weight, had originally lost that weight in a fairly quick manner.
Foods that can help
There are some foods that can be a bit more helpful than others though. Those foods are ones higher in protein and fiber. Both of these nutrients provide more satiety and help to create that fullness feeling. As discussed earlier, that fullness feeling can be a challenge so focusing on protein and fiber rich foods can help ease some of those hunger pains.
Increasing one’s protein intake will also help maintain muscle mass. We work hard for our muscle and if we cut weight we want to make sure it isn’t lost. Eating extra protein helps the body to repair and rebuild any potential muscle damage. Aiming for right around 1 gram of protein per pound of body weight is a good reference point.
Diet breaks and refeeds
There are different theories on the best way to reduce calories for weight loss. The most common and typical strategy is a continuous calorie restriction. This is where day in and day out calories are pulled back a bit. Some feel that this long term restriction can cause the body to adapt and slow metabolism down. Based on this thinking, adding in some times for a diet break or a refeed can help avoid that slow down. What this can typically look like is 5 days of a bit more sever restriction with then going back up to a weight maintenance level of calories for 2 days. Overall there is still a total calorie deficit resulting in a similar weight loss.
Study so far show no actual difference between the two strategies. For athletes though, strategically adding in a refeed can be great when those are timed around competition when maximum performance is the key. The biggest difference in these strategies seem to be the psychological effects. If being able to have a day or two of maintenance calories allows someone to relax a bit and overall help increase the sustainability of their diet then it’s worth it. For those who would feel worse with bouncing back and forth, the consistent restriction is better. Everyone responds differently to different things so it’s finding what works for that person specifically.
Key points to limit metabolism changes
– Slow and stead rate of weight loss
– Increase protein intake
– Focus on high fiber foods
– Caloric deficit is the goal
– Best eating strategy for caloric restriction is unique to each person
– Continue lifting weights to maintain muscle mass
Study referenced: click here