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6 Healthy Ways to Lose Weight From Nutrition Expert Eric Rimm

Some of the most frequent questions our users ask are about losing excess weight. We compiled these questions and shared them with Dr. Eric Rimm, Professor of Nutrition and Epidemiology at the Harvard School of Public Health. Here’s what we learned.

Excess weight can be a tricky thing. Not everyone gains it for the same reasons. Part of the reason has to do with genetics. Another element of it involves behavioral factors, as Dr. Rimm explains. For example, what you ate as a six-year-old probably impacts what your brain perceives as enjoyable to eat now.

Dr. Rimm says there’s no one secret diet that works for everybody. 

“There now have been many studies conducted that train participants to eat certain diets for two or three years. While a few types of diets clearly show more benefits than others, they usually don’t work for everybody in the study. What we do know is that one of the least successful diets is a low-fat diet.”

A lot of people assume that because fat is a source of calories, eliminating it from their diet will help them lose weight, but most low-fat foods are usually full of highly processed carbs, which makes them less healthy.

One of the least successful diets is a low-fat diet.

That said, a vegetarian diet that’s low in fat can be very healthy if you eat the right foods. 

“However, most low-fat diets, at least in the US, are composed of processed foods,” he explains. “They are the least healthy route. People may lose weight during the first three months, but they always gain it back and most gain back more weight than they started off with.” 

Some diets are better at keeping the weight off, for example, the Mediterranean diet, which calls for eating fruits, vegetables, healthy vegetable oils, and whole grains. On the subject of the Mediterranean diet, Rimm says, “It also contains small portion sizes of unprocessed meats and fish and, for people who can control their consumption, a glass of wine. Regardless of the diet, though, don’t forget about regular exercise.”

“Keeping track of calories is hard, but I think it’s a good place to start in terms of reminding yourself how many calories some foods contain,” says Dr. Rimm. 

He suggests starting by tracking what you eat for three or four days. Write down everything you put in your mouth. Then, at the end of the day, you can look up how many calories each food contributed to your daily intake. 

“I think it’s a useful tool just to help people start learning about what’s in foods because you don’t learn that at school, at least in the United States. You can look at a package and quickly see how many calories it contains, but you don’t think about that every time you have a meal or during the course of the day.”

“I think one area where good science has been done concerns eating at night,” says Dr. Rimm.

He provides the example of people who have their main meals either midday or early evening. Then, later in the evening, they reach for a bunch of snacks before they go to bed. These snacks can add up, especially if they are going to bed.  

When you sleep at night, your body’s hormones fluctuate, and you may be less likely to burn off calories with movement and more likely to store calories as fat. According to Dr. Rimm, it’s not a good idea to eat at 10 or 11 o’clock at night, leaving food to digest while your body rests. 

“I don’t think you should starve yourself, but when you finish eating at six or seven o’clock, it’s a good idea to stop eating for the day. Even I struggle with this advice!”

People don’t usually think about sleep because it’s not calorie-based, but healthy sleep is important, according to Dr. Eric Rimm.

Getting enough sleep gives your body time to reset and focus on metabolism. Those hormones that fluctuate in the middle of the night are vital for burning fat. 

Getting enough sleep gives your body time to reset and focus on metabolism. Those hormones that fluctuate in the middle of the night are vital for burning fat.

“Getting at least 7–8 hours of sleep is important, especially for a 25- or 30-year-old woman who’s thinking about having children or may already have a child and is up in the middle of the night because of her child.” 

He says it’s also good to get at least seven hours of sleep to help keep your weight stable. 

Another important aspect to keeping excess weight off is recognizing that it’s a life-long process, according to Dr. Rimm. 

He says there are some extreme diets you can go on to achieve quick weight loss; however — “keep in mind that when you go off that diet, you will almost always gain the weight back, plus more.” 

“When you’re thinking about losing weight or keeping your weight stable, it’s important to ask yourself what you’ll be comfortable doing a year or 18 months from now,” says Dr. Rimm. 

He advises thinking about the changes you want to make and asking yourself a few questions. Would you still be doing this now if you’d started six months ago? Is the diet too expensive or too extreme? For example, will it be challenging to go out with friends because you can’t eat what’s on the menu or can you eat at a friend’s house without making them prepare a whole separate meal for you? Think about your diet and how it fits into your life.

It’s really hard when you don’t see results after 3–7 days. 

Any diet that has you lose a lot of weight in seven days is too extreme, according to Dr. Rimm. It probably means you’ve lost a lot of water weight, not fat. 

He says there are diets you can go on specifically to get rid of water. “When you step on the scale, you say, ‘Wow, this is really working. I’m on a high-protein diet. Look how much weight I’ve lost.’ That’s not fat; that’s just water weight loss at the beginning.” 

Dr. Rimm explains that everybody’s weight fluctuates, for women even more than for men. Your weight fluctuates during the course of your menstrual cycle, even day to day. So losing weight can be challenging. 

“That’s why I suggest not looking at the scale every day. You might get frustrated thinking that your efforts aren’t working. Look at it once a week, write down your weight, and if you are cautious about what you’re eating, you’ll see a small decline. That’s the best way to lose weight.”

Dr. Rimm says that once you start monitoring your progress month to month — not day to day — you will feel most rewarded. Start by keeping your weight stable, then work on losing a little bit. 

“Diets — like the Mediterranean diet, high vegetable diet, or even some high-protein diets that don’t have a lot of red meat — remove highly processed carbohydrates and unhealthy saturated fat over the long-term. These are diets people can stay on because the food tastes good. They can continue the diet because they can still be with friends and have a regular diet. These people tend to keep the weight off. It’s a life-long struggle, but it’s important to tackle it.”

Dr. Rimm says that very few diets work on food alone. Exercise is important, but you have to use both in tandem — “Weight loss isn’t due to exercise alone, not unless it’s an extreme form of exercise. It’s hard to lose weight just by exercising.”

As he explains, if you ignore your diet but run for an hour a day, this usually doesn’t work for weight loss. Of course, that’s not the case for people training for marathons. They do lose weight because they burn everything they eat. 

Diets work best when you exercise at least every other day or more. And exercise can be anything that makes you sweat.

“Diets work best when you exercise at least every other day or more,” says Dr. Rimm. “That doesn’t mean paying a lot of money and going to a gym and using fancy machines. Exercise can be anything that makes you sweat. If you can go for a walk, a really fast walk that gets your heart rate up, that’s great.” 

“Of course, it is fine if you join a gym to run on a treadmill or use an elliptical, but it’s important to find something that’s easy and can be part of your life and not something you hate or is a struggle to do regularly.” Something as simple as riding your bike to work, even if it’s just 15 minutes one way, can get your heart rate up and counts as exercise.

Dr. Rimm suggests people find a healthy diet that works for them and figure out how to make regular exercise fit in their lives. Both of these activities are easier if you can do them with someone and if there’s a support system around you. 

“A lot of fancy diets work because there’s a group that talks about what they find successful — a support group. It’s common for a couple with a family to eat healthily and lose weight together.” And remember — doing it together is always easier than cooking one thing for one person and something else for the other person.

Exercise is the same way, Dr. Rimm says. It’s easier to meet outside to go for a walk or run or to meet at the gym with a group or a buddy. That way, you can’t say ‘I don’t want to go to the gym’ because one of your friends is there waiting for you. It’s also easier when you can socialize while exercising. “Just make sure you don’t forget to exercise!” jokes Dr. Rimm.

If you’re wondering what foods to eat during the day, read part 1 of the interview with Professor Rimm

And in the second part of his interview, Professor Rimm tells Flo about the dangers of unhealthy eating

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