Soup for weight loss

The energy density of soup

Soup works because of energy density, which just means calories per bite. In a Penn State study in the journal Appetite, 60 normal-weight adults ate a vegetable soup of about 172 calories 15 minutes before lunch, once a week for 5 weeks. On soup days they took in about 134 fewer calories at lunch, soup included. The authors report that as a 20% reduction. It didn't matter whether the soup was chunky or pureed.

That's a real effect with a real limit. It was one meal at a time, in a lab, in people who weren't trying to lose weight, so it can't tell you what happens over months.

Think about it this way. A cup of potato chips has about 150 calories and weighs about an ounce. A cup of vegetable soup has about 75 calories and weighs about 8 ounces. It's the same volume in your stomach for half the calories, and your stomach's stretch receptors respond to volume as well as calories.

Barbara Rolls at Penn State, the researcher behind the Volumetrics approach, tested a sharper version. In a 1999 study, 24 lean women ate one of three snacks with the same calories before lunch: a chicken rice casserole, the same casserole with a glass of water, or a soup made of exactly those ingredients. After the soup, they ate about 27% less at lunch, and they didn't make up for it at dinner. The casserole with water did nothing extra. Water built into the food fills you up in a way water beside it doesn't.

Protein in soup for weight loss

Here's where most soup diets fall apart: they're vegetable water with very little protein. You'll lose weight eating 800 calories of cabbage soup a day, and you'll be likely to lose more muscle along the way than you need to. For why protein matters so much during weight loss, see our 100 Best Foods for Weight Loss guide.

In a calorie deficit, your body can break down muscle for energy unless you give it enough protein. A review in the American Journal of Clinical Nutrition found that higher-protein diets during calorie restriction preserved more lean mass in short, tightly controlled trials, with less consistent results in longer ones. It also describes a practical target of about 25 to 30 grams a meal.

A good range for most people is 20 to 35 grams of protein per bowl. That's about 4 to 6 ounces of raw lean meat, 1.5 to 2 cups of beans or 12 to 14 ounces of tofu, depending on the firmness. Build the soup on shredded chicken, turkey, lean ground meat, beans, lentils or tofu.

Severe restriction also makes maintenance harder, whatever food it's built from. That's the argument against a vegetable soup cleanse, and it's why this guide treats soup as a meal rather than a fast.

Fiber in soup for fullness

Soup is an easy way to pack in fiber-rich vegetables without much effort. Most Americans fall short of the recommended 25 to 38 grams of fiber a day, as the Mayo Clinic notes, and a large bowl of vegetable-and-bean soup can deliver 8 to 12 grams.

Soluble fiber, from beans, oats and some vegetables, forms a gel that slows digestion. Insoluble fiber, from leafy greens, carrots and celery, adds bulk. Both help with fullness in different ways.

Fiber also slows how quickly carbohydrates are absorbed, which helps smooth out blood sugar. That's part of why a vegetable-bean soup tends to hold you longer than a cream soup with the same calories.

Top soups for weight loss

These soups combine high volume, enough protein and low calorie density:

Typical homemade ranges per 2 cups, approximate

Soups that need portion awareness

These can work for weight loss, but you'll need to watch the portion or add something:

• Tomato soup: often lower in protein, at about 2 to 8 grams a serving. It's good as an appetizer or with a protein-rich side, but it won't hold you as a meal. A cup runs about 80 calories made from canned with water, about 140 with 2% milk and up to about 180 with cream.
• Split pea soup: decent protein at 8 to 12 grams and good fiber at 6 to 9 grams, but it can be calorie-dense if made with ham hock or bacon. A cup runs 180 to 250 calories. Choose versions with lean ham or go vegetarian.
• Butternut squash soup: nutrient-rich, but typically low in protein at 2 to 6 grams and sometimes higher in calories, at 150 to 250 per cup when made with cream. It works best as a side or an appetizer, not a main dish.

Soups to limit for weight loss

• Cream-based soups: clam chowder, broccoli cheddar, cream of mushroom. Canned versions are lighter than their reputation, with USDA listing cream of mushroom at about 97 calories a cup with water and New England clam chowder at about 154 a cup with 2% milk. Restaurant and homemade versions can run 300 or more a cup, and a big bowl can reach 600 to 700 before the crackers. All of them are low on protein and fiber for the calories.
• French onion soup: the cheese and bread are the issue. A restaurant portion can run 800 to 1,000 calories with 30 to 40 grams of fat, depending on how much cheese they're using.
• Restaurant ramen: the broth can carry 2,000 mg of sodium or more, plus fat. Many bowls top 500 calories before toppings, and most of what's left is noodles.
• Loaded baked potato soup: cream, cheese, bacon and sour cream. It's delicious and can reach 400 calories a cup, so save it for special occasions.

How to read soup labels

• Calories: aim for 150 to 200 per cup, or 300 to 400 for 2 cups. That leaves room for sides and snacks while you stay in a deficit.
• Protein: at least 10 grams per cup, ideally 15 or more. Under 10, plan to add protein separately.
• Fiber: look for 3 grams or more per serving. This is where vegetables and beans do the work.
• Sodium: the tricky one. The FDA puts the daily limit at less than 2,300 mg. Split evenly over three meals, that's about 770 mg each, so 600 to 700 leaves room for snacks. Look for options with 400 to 600 mg per serving, or dilute higher-sodium soups.
• Saturated fat: keep it under 3 grams per serving. Higher amounts usually mean cream or fatty meat, which raise the calories quickly.

Soup brands to compare

• Canned soups: look at Pacific Foods, Amy's Light in Sodium and Progresso Light. Compare the labels, because varieties within one brand differ a lot.
• Refrigerated soups: often fresher-tasting but more expensive. Whole Foods 365, Trader Joe's and Panera at-home options can work if they meet the numbers above.
• Frozen soups: an underused option, with better texture than many canned soups and easy portions. Tabatchnick and Kettle Cuisine have some choices worth checking.

Budget soup for weight loss

Soup is one of the better values in weight loss food if you make it yourself. A batch of 8 to 10 servings typically costs $12 to $18, or about $1.50 to $2.00 a serving. A single can of premium soup costs $3 to $5.

Some ways to keep it low: buy a rotisserie chicken and use the bones for broth, pick up frozen vegetable mixes on sale, stock up on canned beans and tomatoes, and buy bone-in chicken thighs when they're on sale, debone them and save the bones for stock. For more budget strategies, see our 10 Healthy, Cheap Meal Prep Ideas.

Rules for better weight loss soup

1. Start with good broth or stock. Your soup is only as good as its base. Use low-sodium chicken, beef or vegetable stock, because you can always add salt and you can't take it away. Homemade is ideal, and good store-bought works fine.
2. Layer your aromatics. Start by sauteing onions, celery and carrots in a little olive oil or cooking spray. That builds deep flavor with few calories. Add garlic in the last minute so it doesn't burn.
3. Cook vegetables in stages. Hard vegetables like carrots, celery and potatoes go in first. Medium-firm ones like zucchini and bell peppers go in mid-cook. Spinach and kale go in at the very end. That keeps everything from turning to mush.
4. Time the protein. Poach raw chicken or turkey in the broth first, remove it, shred it and add it back at the end. Add precooked protein or beans in the last 10 minutes, just to heat through, since overcooked protein goes rubbery.

Soup cooking methods

• Stovetop: you get the most control over timing, and you can adjust flavors as you go. Most soups take 45 to 60 minutes.
• Slow cooker: add everything except delicate greens and dairy in the morning, cook on low for 6 to 8 hours and add the greens in the last 15 minutes. Check the liquid level, since you may need more broth near the end.
• Pressure cooker: saute the aromatics with the saute function, add everything else and cook on high pressure for 10 to 20 minutes, depending on the protein. It's especially useful for tough cuts of meat and dried beans. Let it release naturally for 10 minutes, then quick release so the broth doesn't spray.
• Sheet pan plus stovetop: roast your vegetables at 425°F for 20 to 25 minutes until caramelized, then add them to a broth-based soup. Roasting brings a sweetness and depth that simmering won't.

How to fix common soup problems

• Too watery: simmer uncovered for 15 to 20 minutes to reduce it. Or blend 1 to 2 cups of the soup, vegetables and all, and stir it back in, which adds body without cream.
• Too bland: taste as you go. Most bland soup needs acid, not more salt, and a tablespoon of lemon juice at the end brightens everything. If it's still flat, try a splash of soy sauce, a teaspoon of tomato paste or some nutritional yeast.
• Too salty: dilute it with unsalted broth or water and add more vegetables. The old trick of simmering a halved potato doesn't pull salt out, since a potato soaks up the salty liquid along with the salt. Dilution is what works.

How to store this soup

Refrigerator: store in airtight containers for 3 to 4 days, per the FDA storage chart. It often tastes better the next day.

Freezer: cool it, then portion it into individual containers, leaving 1 inch of headspace for expansion. It keeps its best quality for 2 to 3 months. Thaw overnight in the refrigerator, then reheat on the stove or in the microwave.

Smart soup storage

• For the fridge: glass containers with tight lids don't absorb odors, clean easily and let you see what's inside. Plastic works too, but it may stain from tomato-based soups.
• For the freezer: freezer-safe containers or heavy-duty freezer bags work best. Freeze bags flat on a sheet pan, then stack them once frozen, which saves a lot of space. Label everything with contents and date.
• Portion sizes: freeze in 2-cup portions for single meals and 4-cup portions for two people or bigger appetites. Having both helps you avoid eating a whole container just because you thawed it.

Which soups freeze best

Some soups freeze better than others. Broth-based soups with vegetables and protein freeze well. Soups with potatoes can get grainy, though they're still safe. Soups with pasta can go mushy, so consider cooking the pasta fresh and adding it to the reheated soup. Cream-based soups can separate, so stir well when reheating.