Let's be real for a second. If you're looking into a 700 calories a day meal plan, you’re probably trying to lose weight fast. Like, yesterday fast. Maybe there’s a wedding coming up, or maybe you’re just fed up with feeling sluggish and want a total reset.
I get it. The lure of "rapid weight loss" is powerful.
But here is the thing: 700 calories is tiny. It’s "toddler-sized" portions for an adult human being. Technically, the medical world classifies anything under 800 calories as a Very Low-Calorie Diet (VLCD). These aren't just casual diets you pick up from a magazine; they are metabolic interventions. When you drop your intake that low, your body doesn't just "burn fat"—it starts a complex, and sometimes messy, internal negotiation for survival.
The biology of the 700 calories a day meal plan
Your Basal Metabolic Rate (BMR) is the energy your body needs just to keep your heart beating, your lungs inhaling, and your brain firing while you lie perfectly still. For most adults, that number sits somewhere between 1,300 and 1,800 calories.
By eating only 700, you are creating a massive deficit.
Initially, you’ll see the scale drop. Hard. In the first week, a lot of that is glycogen—the stored carbs in your muscles that hold onto water. When you use that fuel up, the water goes with it. You feel lighter, your jeans fit better, and you think you’ve cracked the code.
But then, the adaptation kicks in. Dr. Kevin Hall at the National Institutes of Health has done extensive research on "metabolic adaptation." Essentially, your body realizes it’s in a famine. It gets efficient. Your heart rate might slow down. You’ll feel colder because your body is cutting back on "unnecessary" heat production. You’ll move less without even realizing it—a phenomenon called NEAT (Non-Exercise Activity Thermogenesis) drops off a cliff.
👉 See also: Does Birth Control Pill Expire? What You Need to Know Before Taking an Old Pack
You aren't just losing fat; you're losing leverage over your future metabolism.
What does 700 calories actually look like on a plate?
It's sparse. If you aren't careful, you end up eating three "meals" that look more like snacks.
A typical day might start with two egg whites and a handful of spinach. That’s maybe 50 calories. Lunch might be a 4-ounce piece of grilled chicken breast over a massive pile of shredded cabbage and cucumber with lemon juice. No oil. No dressing. That’s another 200 calories. Dinner could be a piece of white fish like cod with steamed asparagus and a small serving of cauliflower rice.
You’ve got maybe 150 calories left for a small apple or a scoop of Greek yogurt.
The volume has to be high, or your stomach will feel physically empty. We call this "volume eating." You lean heavily on leafy greens, celery, and radishes because they provide bulk without the caloric hit. But honestly? It gets boring fast. The psychological fatigue of weighing every single blueberry is what usually breaks people long before the hunger does.
The risks nobody mentions in the brochures
Rapid weight loss isn't just about "willpower." There are actual physiological dangers when you stay on a 700 calories a day meal plan without medical supervision.
✨ Don't miss: X Ray on Hand: What Your Doctor is Actually Looking For
One of the big ones is gallstones. When you lose weight extremely quickly, your liver secretes extra cholesterol into bile, which can form stones. It’s incredibly painful and often ends in surgery. Then there’s the heart. Your heart is a muscle. If your body is desperate for protein and energy, it doesn't just take it from your biceps; it can take it from your heart tissue.
Studies published in The Lancet have historically looked at VLCDs in clinical settings. Usually, these are for people with a high BMI who need to lose weight before a life-saving surgery. In those cases, they use specialized shakes fortified with every single vitamin and mineral the body needs.
If you try to do this with "real food" alone, you will almost certainly hit a micronutrient wall. You'll run low on potassium, magnesium, and B vitamins. Your hair might start thinning. Your nails get brittle. You might feel "brain fog" where you stare at a simple email for ten minutes because your brain, which runs on glucose, is being forced to run on emergency fumes.
Why protein is the only thing that matters (if you do this)
If you are absolutely set on a very low calorie intake, protein is your only shield.
When you eat 700 calories, your body is looking for amino acids. If you don't eat enough of them, it harvests them from your muscles. This is a disaster. Muscle is metabolically active; it burns calories just by existing. If you lose muscle, your BMR drops even further.
To mitigate this, you have to prioritize protein above all else. We're talking 0.8 to 1 gram of protein per pound of your target body weight. On a 700-calorie budget, that basically means your entire diet is chicken breast, egg whites, and white fish. There's almost no room for fats or carbs.
🔗 Read more: Does Ginger Ale Help With Upset Stomach? Why Your Soda Habit Might Be Making Things Worse
Is that sustainable? For 99% of people, no.
The "Rubber Band" effect
The biggest issue with a 700 calories a day meal plan is what happens when you stop.
Most people use these plans as a "kickstart." They do it for two weeks, lose 10 pounds, and then go back to "normal" eating. But your "normal" is now too much for your suppressed metabolism. Because you've likely lost some muscle mass, you burn fewer calories than you did before you started the diet.
This is why people often gain back 12 pounds after losing 10. It’s the classic yo-yo.
How to actually move forward safely
If you’re still convinced you want to try a massive deficit, you need a strategy that isn't just "starve and hope."
- Get a blood panel first. See where your iron and vitamin D levels are. Don't start a deficit if you're already deficient.
- Supplementation is mandatory. You can't get enough nutrition from 700 calories of food. You’ll need a high-quality multivitamin and potentially an electrolyte powder (sodium, potassium, magnesium) to prevent dizziness and heart palpitations.
- Keep it short. Clinical VLCDs are rarely done for more than 12 weeks, even under a doctor’s eye. For a DIY approach, anything beyond a few days is risky.
- Focus on Fiber. Psyllium husk or massive amounts of greens are the only way to keep your digestive system moving. Constipation is a very real side effect of eating so little.
Instead of a flat 700 every day, many experts suggest "intermittent" low-calorie days. The 5:2 diet, for example, has you eat normally for five days and around 500-600 calories for two non-consecutive days. This seems to be much easier on the metabolism and the psyche.
The truth is, weight loss is a long game. A 700 calories a day meal plan is a sprint. Sprints are great for the finish line, but if you try to sprint a marathon, you’re just going to collapse before you get anywhere meaningful.
Actionable Next Steps
- Calculate your TDEE. Use an online Total Daily Energy Expenditure calculator to see how much you actually burn.
- Aim for a 500-calorie deficit. It’s boring, but it’s the gold standard for keeping the weight off long-term without losing your hair or your sanity.
- Prioritize strength training. If you are cutting calories, you must tell your body to "keep the muscle" by lifting weights.
- Consult a professional. If you genuinely feel you need a VLCD, talk to a bariatric physician or a registered dietitian who can prescribe a medically formulated program that won't leave you malnourished.