How do you measure your weight? Probably with a scale, right? Sure, that’s not bad, but have you considered using a calendar?We know what you’re thinking—you can’t weigh yourself with a calendar. But new research suggests that you should give it a try. That is, you get your weight using a scale (though BMI may be a more useful measurement), but keep a calendar handy to properly interpret the number on the dial. A January 2014 study published online in the journal Obesity Facts found that most people lose weight over the course of the week and then gain some on the weekends. That means that you’re likely to be lightest on Friday and heaviest on Sunday.

What sets overall weight-gainers apart from those who are able to lose weight is what happens between Monday and Friday. Weight-losers have what the researchers call a “stronger compensation pattern,” which means that their downward weight fluctuation started immediately after the weekend and continued all the way through Friday. On the other hand, people who gain weight showed more variability in their weight fluctuations and did not show a clear decrease during the week.

What does this tell us? It reminds us that fluctuating up to 5 pounds per week is totally normal. It shows that it’s typical to go out and have a good time over the weekend, enjoying a brunch with friends or a fancier dinner than you muster most nights after work. (Although we have to wonder: Are the real weight-losers those that eat better on the weekends too?) And most importantly, it reveals that (if you are typical) the decisions you make during the week are going to have the biggest impact on your weight—and therefore on your health and beauty.

Here are four tips for maintaining healthy habits—and a healthy weight—from Monday morning ’til Friday night:

1. Have a healthful breakfast:
Your mom always told you that breakfast is the most important meal of the day. Well, for people who worry about their weight, breakfast is especially important. A high-glycemic breakfast full of carbs that break down fast and spike your blood sugar will not only leave you hungry well before lunch, it will also make you crave sweets all the way to dinnertime. To keep yourself full and stave off cravings later on, make a breakfast that includes only whole grains (such as steel cut oatmeal), and protein (such as egg whites, turkey sausage or a tofu scramble).

2. Eat the same thing for lunch every day:
A study by researchers at the University of Buffalo and the University of Vermont found that when people ate the same lunch every day for a week, they consumed 125 fewer calories on day five than they had on day one. On the flip side, participants who varied up their midday meals ended up eating 45 more calories by the end of the week.

3. Get a food buddy:
Research shows that if you eat your meals with a like-minded friend, you will both order healthier options and be happier with what you get. Hearing your friends choose healthy, lower-calorie options makes you want to choose healthy, lower-calorie options. It’s a form of peer support. Need an email buddy? Try Enforcer e-coaching (there is a charge).

4. Try meal planning:
During the week, when we’re all running around worrying about work and errands and kids and more, sometimes what we eat becomes an afterthought. Make it a forethought instead. Take 30 minutes over the weekend (you might not even need that long) to plan out a menu of dinner and lunches for the week, then shop for those meals and make them Sunday evening. You can portion them ahead of time, and freeze some for later. That way, you’ll have a healthy, well-thought-out meal literally at your fingertips when you’re running off to work, or coming home exhausted from a long day.

READ MORE: Take the Eat Pretty Quiz