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How to Lose Weight Without Harming Your Health

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

Excess weight is 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. For example, what you ate as a six-year-old probably impacts what your brain perceives as enjoyable to eat now. 

Is there a diet that helps everyone?

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 2 or 3 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

People think “Fat is calories, so I want to take fat out of my diet”. That’s the wrong thing to do because most low-fat foods are usually full of highly processed high carb foods, which makes them less healthy. 

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. They are the least healthy route. People may lose weight during the first 3 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. It calls for eating fruits, vegetables, healthy vegetable oils, and whole grains. It also contains small portion sizes of unprocessed meats and fish and for some people who can control their consumption a glass of wine.  Regardless of the diet though, don’t forget about regular exercise.

Does counting calories help?

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. 

Start by tracking what you eat for 3 or 4 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 really 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. 

So, I would say it’s not a bad place to start. Just track what you eat during the day for 3 or 4 days in a row and write it down. You will be surprised when you learn how much a burger, pizza, fries or a large soda contribute to your daily intake. 

What are the healthy ways to lose weight?

Tip #1 Stop eating late at night

I think one area where good science has been done concerns eating at night. 

Some people have their main meal either midday or early evening. Thy later in the evening they reach for a bunch of snacks before they go to bed. These snacks can add up especially if you 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.  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 6 or 7 o’clock, it’s a good idea to stop eating for the day. Even I struggle with this advice! 

Tip #2 Get enough sleep

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

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 or 8 hours of sleep is important, especially for a 25, 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. 

Find a way to get at least 7 hours of sleep to help keep your weight stable. 

Tip #3 Make your healthy habits last a lifetime

Another important aspect to keeping weight off is recognizing that it’s a life-long process. 

Losing weight for 3 months to fit into a dress for your best friend’s wedding might be important to you. If that’s your goal, okay. There are some extreme diets you can go on to achieve that.

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. 

Think about the changes you want to make and ask yourself a few questions. Would you still be doing this now if you’d started 6 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 you can 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. 

Tip #4 Don’t expect to see results right away

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

Any diet that sees you lose a lot of weight in 7 days is too extreme. It probably means you’ve lost a lot of water weight, not fat. 

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 really high-protein diet, look how much weight I’ve lost”. That’s not fat, that’s just water weight loss at the beginning. 

Everybody’s weight fluctuates, women more so than man. You fluctuate 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 really cautious about what you’re eating, you’ll see a small decline. That’s the best way to lose weight.  

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. 

That’s why 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 I think it’s important to tackle it.

Tip #5 Exercise more

I will say that very few diets work on food alone. 

Performing some form of exercise is important. 

But 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.

 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. 

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. 

If you ride a bicycle to work, 15 minutes one way and 15 minutes back, you’re getting your heart rate up, which is great.

Of course, it is fine if 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.

You can’t go to the gym for three weeks and then think “I can’t do it, it’s so expensive, I hate it” or whatever the case might be. 

Tip #6 Find support

I tell people to find a healthy diet that works for them and to figure out how to fit exercise in. Both of these activities are easier if you can do it 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 husband and wife with a family to eat healthily and lose weight together. 

It’s always easier than cooking one thing for one person and something else for the other person.

Exercise is the same way. 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!

Find friends with similar interests. It’s easier to keep weight off because you’re doing it together. 


If you wonder 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 told Flo about the dangers of unhealthy eating

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