By Balveer Singh Rathore, Editor · Last updated: September 26, 2026 · How we write
The 21-Day Smoothie Diet is a paid e-book programme that replaces two meals a day with fruit-and-vegetable smoothies for three weeks. You’ll probably lose some weight because you eat fewer calories, but there’s no research on the programme itself, many smoothies are low in protein and high in sugar, and weight often returns afterwards.
Our verdict: not recommended as a weight-loss plan. Smoothies can be part of a healthy diet, but a balanced calorie deficit with regular meals is safer and easier to keep up. We have no affiliate relationship with this programme; earlier versions of this page contained promotional links, which we’ve removed.
This article is general information, not medical advice. If you have a health condition, are pregnant or take medication, talk to your doctor before changing your diet, exercise or supplements. Read our disclaimer.
What is the 21-Day Smoothie Diet?
The programme was created by health coach Drew Sgoutas and is sold online as an e-book with recipes, shopping lists and meal plans. Healthline reported its price as $47 at the time of their review. It’s heavily promoted through affiliate websites, which is why many online “reviews” are overwhelmingly positive.
How does it work?
- Replace two meals a day with the programme’s smoothies.
- Eat one “normal” solid meal and a couple of healthy snacks.
- An optional 3-day “detox” replaces all three meals with smoothies.
- Follow the plan for 21 days, and repeat if you want.
Does the 21-Day Smoothie Diet work?
It can lead to short-term weight loss, mainly because smoothies replace larger meals and you eat fewer calories. But there’s no published research on this specific programme, and claims about better skin, gut health or “detox” aren’t supported by evidence. Your liver and kidneys already handle detoxification.
Concerns and possible side effects
| Concern | Why it matters |
|---|---|
| Low protein | Many fruit-based smoothies have only a few grams of protein, which can leave you hungry and cost you muscle |
| High sugar | Several fruits, juice or honey per smoothie add up; people with diabetes should be careful |
| Too few calories for some | Very low intake can cause tiredness, dizziness and nutrient gaps |
| Hard to maintain | Weight often returns when normal eating resumes |
| Not suitable for everyone | Not advised in pregnancy, for teenagers, or for people with diabetes, kidney disease or a history of eating disorders without medical advice |
A better way to use smoothies
If you like smoothies, use them to replace one meal or a snack, not two meals, and make them balanced:
- Protein: curd, milk, paneer, tofu, or a scoop of protein powder
- Fibre: 1 fruit plus vegetables like spinach or cucumber
- Healthy fat: a spoon of nut butter, chia or flax seeds
- No added sugar: skip honey, sugar and fruit juice
3 balanced smoothie recipes
- Banana-oats protein smoothie: 1 small banana, 2 tbsp oats, 1 cup low-fat milk, 1 tbsp peanut butter, cinnamon.
- Green curd smoothie: 1 cup spinach, ½ cup curd, ½ apple, ½ cup water, 1 tsp chia seeds, a few mint leaves.
- Berry-paneer smoothie: ½ cup berries or papaya, 50 g paneer or tofu, ¾ cup milk, 1 tsp flaxseed.
For a sustainable plan with regular meals, see our 7-day Indian diet plan for weight loss and what research says about weight loss drinks.
Frequently asked questions
Does the 21-Day Smoothie Diet really work?
You may lose weight in three weeks because the plan cuts calories by replacing two meals with smoothies. However, there’s no published research on the programme, many recipes are low in protein and high in sugar, and weight often comes back afterwards. A balanced calorie deficit with regular meals is more sustainable.
How much weight can you lose on the 21-Day Smoothie Diet?
Results vary with your starting weight and how many calories you eat. Big numbers promoted online come from testimonials, not studies. A safe, sustainable rate is about 0.5 kg a week; faster losses on very low-calorie plans are often water and may include muscle.
Is the 21-Day Smoothie Diet safe?
It may be safe short-term for healthy adults, but it can be low in protein and calories and high in sugar. It’s not suitable for pregnant women, teenagers, people with diabetes or kidney disease, or anyone with a history of eating disorders without medical advice.
Who created the 21-Day Smoothie Diet?
It was created by Drew Sgoutas, who is described as a health coach, and is sold as an online e-book. It’s widely promoted through affiliate marketing, so many online reviews earn a commission when readers buy it.
Can I replace meals with smoothies to lose weight?
Replacing one meal a day with a balanced smoothie containing protein, fibre and healthy fat can fit into a weight-loss plan. Replacing two or three meals makes it hard to get enough protein and nutrients. Avoid added sugar and fruit juice in your smoothies.
What is a healthy smoothie for weight loss?
A good weight-loss smoothie includes protein (curd, milk, paneer, tofu or protein powder), one portion of fruit, some vegetables like spinach, and a small amount of healthy fat such as chia seeds or nut butter, with no added sugar or juice.